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2005 National DNA Day Online Chatroom TranscriptThis is an archive of the the National DNA Day Moderated Chat held April 25th, 2005. NHGRI Director Francis Collins and genomics experts from across the institute took questions from students, teachers and the general public on topics ranging from basic genomic research, to the genetic basis of disease, to ethical questions about genetic privacy.
Q: St. Ignatius College Prep HS: Are there any specific variations in the human genome that can be attributed to differences between the races? Will some of these variations help to develop individualized therapies? A: Vence Bonham, J.D.: No. “Human Racial Groups” are a social construct. How races are defined has changed over time. Human genetic variation exists across the world which often correlates with self identified race. However, there are no gene variants that are present in all individuals of one “racial group” and in no individuals of another group. Understanding an individual’s ancestry is important for the development of individualized therapies and knowing a person’s “race” or “ethnicity” may or may not tell us very little about that person’s ancestry. Using the construct of race in describing human genetic variation is full of complexities. Q: Eddie Wang, Montgomery Blaire HS: How does methylation of DNA occur and what does it do to protect DNA from being cleaved? A: Belen Hurle, Ph.D.: Methyl group tags in the DNA of humans and other mammals play an important role in determining whether some genes are or are not expressed. Genes unnecessary for any given cell's function can be tagged with the methyl groups. Simpler organisms, such as many types of bacteria and the single-celled yeast, usually do not use methyl group tagged C's in regulating their genes. Some bacteria, but not all, use methyl group tagged A's (mA) for this purpose. However, most bacteria have specific patterns of mC and mA in their DNA as a signal that says "this is my DNA" and acts as part of an immunity mechanism that allows bacteria to destroy the DNA from infecting viruses without destroying their own DNA. In other words, the distinction between "foreign" and "self" DNA is made through a specific methylation of the bacterial DNA, which protects it from cleavage by the restriction enzymes. The viral DNA, which is not protected, is quickly degraded by the restriction enzymes carried by the bacteria. Q: roberto ny: Does every living thing have DNA? A: Belen Hurle, Ph.D.: Yes, every living thing -- plants, animals and even microorganisms -- has DNA. There are biological entities that do not rely on DNA, but they are pretty weird. Some viruses, for example, reproduce through RNA instead of DNA. And then there is an entity called a prion which does not appear to have any nucleic acid, but appears to cause some neurological disorders, including Alzheimer's dissease. Q: Erin,Geneva,NY: What happens on national DNA Day? A: Vence Bonham, J.D.: High school students and teachers across the country come together to celebrate our knowledge about the human genome. There are scientists that are going into high school classrooms across the country to share their knowledge about the human genome. We hope it encouages students to learn more about the human genome. Q: St. Ignatius College Prep HS: Should scientists/corporations have the right to patent genes? What impact does/will this have on genetic research? A: Vence Bonham, J.D.: The purpose of a patent is to provide an incentive (in the form of a time-limited monopoly) to encourage the commercializing of technological innovation. However, when someone patents a genetic sequence, he/she can exclude others from making, using, or selling any tests based on detection of the gene and/or particular mutations in the gene. Consequently, this makes the patent on a gene much more powerful and valuable than many other patents and can cause a limit in the sharing of research knowledge. The International Human Genome Project put its data in the public domain. All the sequence information acquired from the Human Genome Project was immediately deposited into databases that can be assessed on the World Wide Web. Q: Kiran Bhat, Montgomery Blaire HS: Are there special enzymes that unwind/transcribe mitochondrial DNA, as compared to enzymes that help transcribe cellular DNA? A: Belen Hurle, Ph.D.: The mitochondrion is the energy producing organelle in the cell, and the only organelle in animal cells besides the nucleus that contains its own chromosome. Maintenance of mitochondrial function requires the replication and expression of the mitochondrial genome. Remarkably, not a single gene involved in mitochondrial molecular biology is encoded in the compact mitochondrial genome: all of the protein machinery for replication, transcription, and translation (and DNA repair functions) is encoded in the nucleus, and the relevant proteins must be imported into the mitochondrion. Q: mohamed taha alahram egypt: Do stem cells have the same genome as other cells? A: Belen Hurle, Ph.D.: Yes, stem cells have exactly the same genome as the other cells of the body from which they are derived. All cells in the body arise from a single cell, the fertilized egg. And then the fertilized egg changes into every other type of cell in the body. As most cells mature, they lose their ability to change into a different cell type. .Stem cells retain their ability to change into another type of cell. All cells of the body have exactly the same DNA, including the stem cells. Q: Erin, Maine: Have there been certain genetic trends found in people of certain race and ethnic backgrounds? A: Vence Bonham, J.D.: Yes. There are a number of studies that show that certain allele frequencies are clustered in the indviduals of certain self-identified racial and ethnic backgrounds. Q: Shanaenae, Sveeden: wat year was nucleic acid discovered? A: Larry Thompson: Friedrich Miescher, a chemist, isolated nuclein from the nucleus of pus cells in 1869. The substances were rich in phosphorus and nitrogen and came to be known as nucleic acid. And nucleic acid, of course, is the building block of DNA, the stuff of the genome. Q: Central HS, Helena AR: What are restriction enzymes and how are they used in genetic engineering? A: Belen Hurle, Ph.D.: Hello, Helena. Restriction enzymes are part of the immune system of bacteria. They recognize short sequences in the DNA of infecting phages and cut the DNA (DNA degradation). In genetic engineering they are used as "scissors" that allow researchers to chop big pieces of DNA in a controlled way for analysis and further manipulation. Q: Central HS, Helena AR: Is it possible that later on in the future we will be able to change the way our children look and act? A: Vence Bonham, J.D.: In the future it may be possible. The question is do we want to use technology to change the way our children look and act? What do you think? Q: Central HS, Helena AR: How close are we to cloning, do you think it will really happen? A: Belen Hurle, Ph.D.: Hello, how are you? the answer is, it depends on what organisim you are talking about. Sheeps and cats, for example, have been cloned already. In terms of humans, I think it is technically not possible yet. Most regulatory agencies in most countries around the world are concerned about the ethical implications and have legislation banning human cloning. Q: Clair Briggs, Montgomery Blaire HS: How does mustard gas remove guanine from DNA? A: Belen Hurle, Ph.D.: Mustard gas is a very reactive intermediate and is particularly negative to cellular health as it has a strong tendency to bond to the guanine nitrogen in DNA strands. This leads to either immediate cellular death or, as recent research has found, cancer. Mustard gas is not very soluble in water but is very soluble in fat, contributing to its rapid absorption into the skin. Q: liz: What should our class do for DNA day? A: Vence Bonham, J.D.: Watch the webcast and participate in the chat room. We want you to have fun as well as learn about the human genome. Q: St. Ignatius College Prep HS: Would you personally consider ‘tweaking’ your own child’s genome in order to create a ‘better’, healthier outcome? A: Vence Bonham, J.D.: Today you cannot “tweak” a person’s genome. Gene therapy is an evolving technique used to treat inherited diseases. The medical procedure involves replacing, manipulating, or supplementing nonfunctional genes with healthy genes. Today the procedure is experimental and includes many risks. One example that is currently available is Preimplantation genetic diagnosis (PGD). PGD tests early-stage embryos produced through in vitro fertilization (IVF) for the presence of a variety of conditions. One cell is extracted from the embryo in its eight-cell stage and analyzed. Embryos free of certain conditions can be implanted in a woman's uterus and be allowed to develop into a child. We all have mutations in our genome and I would be hesitant to intervene. These are difficult personal and moral decisions for each person involved. Q: Eric, Newton North HS: Are other forms of life possible without DNA? (Assuming life has metabolic activity and reproduction) A: Belen Hurle, Ph.D.: Hi, Eric! How do you define forms of life? Some viruses have RNA as their only genetic material, but they are not free living organisms. Q: Rose Feinberg, Montgomery Blaire HS: If identical twins have the exact same DNA, then what accounts for their differences in intelligence, sexual orientation, etc.? A: Belen Hurle, Ph.D.: Every human is different from one another, even identical twins because we are all products of the interaction of our genes and the environment in which we live. Even before birth, the environment in which the twins develop is slightly different (Who was born first? Who gained more weight during pregnancy?). The environmental differences keep multiplying and accumulating from birth on, making it impossible to ever repeat a human being. Q: Lisa, Ben Logan High School: Attn: Vence Bonham, What does J.D. stand for? A: Vence Bonham, J.D.: J.D. is a juris doctorate degree. It is a law degree. There is a need for professionals from different disciplinary backgrounds to be involved in genomic research. I conduct research on the social, ethical and legal implications of genomics.
Q: Melissa Frank, Benjamin Logan: How long have you been working on the genome project? A: Larry Thompson: Hi Melissa. The Human Genome Project began in October 1990. The first draft of the genome project was announced in June 2000 and the project was completed in April 2003, about two years earlier than expected. We are now done with the Human Genome Project and are moving on to many projects designed to help scientists and doctors understand the information contained in the genome's digital code. Ultimately, scientists want to identify all of the genes and other functional parts of the genome. Q: Saurov Mahanta, India: Why is DNA not always double stranded? A: Belen Hurle, Ph.D.: Hi Saurov. You are our first person from India! When you separate the two strands of DNA you create two template strands that the cell machinery uses to produce two identical copies of the original molecule. You cannot achieve DNA replication withouth separating the strands first. Q: June Hu, Montgomery Blaire HS: What would happen if half of your introns were removed? A: Belen Hurle, Ph.D.: Hello June, if an intron is not removed, it remains as part of the final RNA molecule. The translation of its sequence alters the sequence of the protein product, most often causing (a) frameshift with premature stop codons or (b) incorrect skipping of exon(s). In the scenario that you describe, many, many of your proteins would not be functional at all (very deadly condition). Q: St. Ignatius College Prep: What role do you see genetic engineering playing in our everyday lives – 10 – 25 – 50 years into the future? A: Bob Nussbaum, M.D.: Genetic engineering will provide us with new tools for diagnosing diseases and developing new treatments. It will also be used to grow replacement tissues in the laboratory to help repair damaged organs. Finally, I expect that we will be able to go in and change defective genetic information and correct it to prevent the disease from developing or progressing. Q: Lindsey, Benjamin Logan High School: When was DNA Day originated, and who came up with it? A: Vence Bonham, J.D.: Congress declared April 25th 2003 as DNA Day to celebrate the completion of the human genome project and the 50th aniversary of the description of DNA. Q: Ravi Umarji, Montgomery Blaire HS, Maryland: How do exonucleases repair DNA in replication A: Belen Hurle, Ph.D.: Hello Ravi, as you know, the main enzymatic activity of DNA polymerases is the 5' ----> 3' synthetic activity. It is possible (but rare) for DNA polymerases to incorporate an incorrect base during replication. Fortunately, these mismatched bases are recognized by the polymerase immediately due to the lack of Watson-Crick base-pairing. The mismatched base is then removed by the 3' ------> 5' exonuclease activity and the correct base inserted prior to progression of replication. Q: St. Ignatius College Prep: Do you see stems cells as the “wave of the future”? A: Bob Nussbaum, M.D.: Stem cells are important tools for developing replacment tissues and organs that have been damaged by disease or injury. I expect stem cells will be very important in helping to treat cancers, spinal cord injuries, and heart disease. All, importantly, by studying stem cells in culture, we can learn how normal stem cells in the body develop into the tissues of the body. The great hope is that we will develop drugs and other substances that will promote one's OWN stem cells to divide and develop and repair damaged tissues. So, I see stem cells as having both a BASIC research role, to help us understand how tissues develop, and an APPLIED role in giving us actual tools for repairing damaged tissues and organs. Q: Chad, maine: What's your favorite chromosome? A: Eric Green, M.D., Ph.D.: For the Human Genome Project, my research laboratory was assigned chromosome 7. Our job was to develop an organized 'map' of this chromosome, which comprises 5% of the human genome. We then were involved in helping to get chromosome 7 sequenced. Our many person-years of effort certainly made chromosome 7 our 'local favorite'-- but in reality the entire human genome is so vast, so fascinating, and so important that it is impossible to really consider any part of your true favorite. Q: Josh, Bellefonaine: What careers are there in this field? A: Kim Kaphingst, Sc.D.: This field has many different types of careers. You can be a genetic researcher or can do other types of research. I study how to communicate information about genetics to people. Other researchers study the ethical questions around genetics. Then other people educate the public about genetics. Q: St. Ignatius College Prep HS: What is the possibility of a human proteome project? A: Eric Green, M.D., Ph.D.: The Human Genome Project demonstrated that a large, focused effort could be mounted to tackle a 'comprehensive' goal-- like determining the entire sequence of the human genome. The notion of using a similar large, high-throughput project to determine the complete set of human proteins is certainly quite reasonable. Certainly, different methods and strategies would be required. Indeed, efforts to develop catalogs of all proteins in certain cells or certain tissues are ongoing. This emerging field is often called 'proteomics'. Q: St. Ignatius College Prep High School: Will genetic therapies, as they develop, be made (realistically) available to the public or will they be too expensive for most to afford? A: Bob Nussbaum, M.D.: This is an excellent and difficult question. If one looks at the history of many medical breakthroughs, treatments haved started out very expensive and then became cheaper as newer and better approaches have come along. For example, iron lungs were very expensive for treating people stricken with polio. Developing polio vaccines was expensive (and paid for primarily by private charitable donations through the March of Dimes, by the way) but is now so cheap that we are having trouble getting companies to make vaccines because their profitability is low. I do believe that in the future, a partnership between the government and private industry will work to make the fruits of genetic research available. However, this is a problem that all of society, not just scientists, not just geneticists, will have to deal with and solve. That's why it is SO IMPORTANT that everyone be aware of what is going on in genetics, not just a narrow group of specialized scientists, but policy makers and economists in the government. Every citizen of the world needs to have an accurate and thorough knowledge. Q: Billy Madison: According to the DNA code, what organism is our closest relative? A: Eric Green, M.D., Ph.D.: The chimpanzee, whose genome was recently sequenced. At a DNA sequence level, we are 98.5% identifical to chimpanzees. Q: Jenna BLHS: How can twins DNA be exactly the same, yet be so different? A: Kim Kaphingst, Sc.D.: There are many things other than DNA that affect how people act. The environment in which you grow up and live in has a big effect on behavior. So, if twins have different groups of friends or are treated differently by other people, they can act very differently. Q: steven woo, Warwick,RI: how old are you people A: Larry Thompson: Hi. We have a roomful of about a dozen folks right now, reading and trying to answer all of your questions. And the age range is from the early 20s to the mid-50s. We have the institute's scientific director, one of the branch chiefs -- both are MDs doing research, among other staff. The range of people who work at the institute range from high school students on internships to very senior, tenure-track scientists with decades of experience. Q: Kyle, PA: Is there current plans to study other animals' genomes? A: Eric Green, M.D., Ph.D.: Genome scientists around the world are actively sequencing the genomes of many other organisms, from bacteria to mammals. The genome sequences of mammals and other vertebrates will be particularly valuable for helping us determine the functional parts of the human genome. This field of 'comparative genomics' uses the evolutionary history recorded in each species' genome to reveal clues about what has and has not been retained in our genomes over millions of years of evolution. Such information provides powerful clues about what parts of our genome perform key functions, such as encoding for proteins or regulating when and/or where certain genes are switched on. Q: St. Ignatius College Prep HS: How can the Human Genome Project be applied to identifying and treating genetic disorders? A: Bob Nussbaum, M.D.: Every person has at least 1 in 1000 bases of DNA different from any other person. This variation in DNA can be of no significance OR can be responsible for differences in our appearance, tendency to various diseases, athletic abilities, personality traits, and many other aspects - but, of course, genes do NOT determine everything. Much of what we are and what diseases we suffer are the result of environmental influences, diet, upbringing, education, etc. Even though there is a complex give and take between genes and environment, we can make progress in finding genetic variation that affects our health and tendency to various diseeases. By finding these changes, we can help people by helpiong them change their "envionment" by letting them know what life style changes, behavior, diet, medications, would be particularly helpful to them or are of less importance than to someone else with different genetic variation. Q: Autumn Aul, Titusville High School: As an upcoming college student I am preparing for a career in biology and genetics. What kind of training is required to become a genetic researcher or a genetic councilor? A: Kim Kaphingst, Sc.D.: A solid background in molecular biology will be important for both of those careers. You might think about biochemistry or biology as an undergraduate major. Working in a research lab is also great preparation. You might also take some psychology courses if you're interested in genetic counseling. Ask your advisor in college about summer internships that will give you practical experience and can help you decide what direction you would like your career to take. Q: brittany price Ben logan: is spider man in any way possible? A: Eric Green, M.D., Ph.D.: Unlikely, in reality. The biology is a bit too complicated to really make a super-hero through a spider bite. BUT, the basic notion of introducing small amounts of new DNA into humans is possible and indeed is used to treat some diseases. This area is known as 'gene therapy.' Q: Olivia, Abingdon High School: How do you actually see the genome? A: Kris Wetterstrand, M.S.: The genome is extremely small and can't be viewed with the naked eye. But since scientists have now determined the order of the chemical units in the human genome, you can go and see that data at a number of web sites including the http://genome.ucsc.edu/cgi-bin/hgGateway. Hit the 'submit' button for an example. Q: ilovedna: Why is DNA so cool? A: Eric Green, M.D., Ph.D.: 4 letters. No upper case or lower case. No punctionation marks. No spaces. YET, it is responible for encoding all the information needed for all free-living organisms on Earth. What isn't cool about that??? Q: fernando, spain: I'm spanish, and I don't control english very good. May be somebody speaks spanish...Me podriais hablar acerca de los futuros projectos q teneis previstos sobre ADN? A: Belen Hurle, Ph.D.: Hola Fernando, El NHGRI tiene muchos proyectos en marcha: por ejemplo, tenemos un programa muy amplio de genetica comparativa en vertebrados y un programa llamado ENCODE que esta analizando el 1% del genoma humano con un detalle sin precedentes buscando todos los elementos que regulan al expresion de los genes comprendidos en ese 1%. Hay muchos mas programas: HapMap, el atlas del cancer humano...si quieres saber mas de estos y otros programas, porque no nos visitas en nuestra pagina web www.genome.gov? gracias por conectar desde Espana! Q: St. Ignatius College Prep HS: What new developing modes of therapy and/or medicines do you find most exciting and most realistic? A: Bob Nussbaum, M.D.: 1. Medications that are designed to target very specific biochemical reactions involved in cancer (example: Gleevec, a treatment specific for a hard to treat form of leukemia) 2. learning how certain tissues in the body develop, by studying stem cells, so we can make these tissues and replace damaged one. Best example: can we remake the "islet cells" of the pancreas that make insulin and thereby cure diabetes. 3. We will find variations in DNA sequence that give a tendency to certain diseases, give people the chance to be tested for these variations, and thereby give them a personal, tailor-made set of medical suggestions to improve their health. Examples: Variations that cause high blood lipids and therefore heart disease can be found and appropriate dietary and medical treatments instituted. Variations that predispose to cancer of various kinds (like breast or colon cancer)can alert people to have more frequent screening tests or even institute preventive treatments. Q: Ashley: How exactly was DNA discovered? What had to be done to find out the sequence? A: Kris Wetterstrand, M.S.: The structure of DNA was determined by James Watson and Francis Crick in 1953. Determining the human sequence was a project that lasted many years, involved hundreds od scientists in many countries and cost millions of dollars. It was a truly unique effort for biologists. The genome, which is large in terms of the number of chemical units had to be broken down into smaller pieces that could be manipulated in the lab and then put back together uses computers. Q: Dr. Reinhart's Class, Newtown Square, PA: Whose DNA was used to sequence the human genome? A: Larry Thompson: The short answer is we don't know. And that was on purpose. The people who donated the DNA used in the Human Genome Project primarily came from Buffalo, N.Y., and were selected from a large pool of volunteers whose DNA was randomized and made anonymous. So, we don't know which individual's DNA was actually sequenced, but we know it is representative of all the DNA in the human genome because it was mapped back to all the chromosomes. Q: St. Ignatius College Prep HS: What areas of genetic research would you advise interested students to keep a watchful eye on, to pursue in their studies? What would you tell them to concentrate on in college and what should they tell their parents they’re planning on doing? A: Eric Green, M.D., Ph.D.: Future genome and genetic scientists would benefit from training in many different areas. Certainly computer science, biology, physics, and/of engineering would provide a strong foundation. Increasingly, we will need teams of talented scientists and clinicians, all bringing different expertise, to tackle the most vexing problems in genetics-- especially those aimed at improving human health. My advice is to gain a broad education, pursuing those areas that interest you most. I must admit that one area I wish I had more formal training in is computer science-- but then again, we were using punch cards when I was in college... Q: Central HS, Helena AR: Can genes determine if someone is going to be a killer? A: Kim Kaphingst, Sc.D.: We do not have any clear evidence that genes determine whether somone will commit crimes like murder. Other things are likely to play an important role in determining a person's behavior. For example, we know the environment in which people grow up has a strong effect on people's behavior and whether they are more or less likely to commit a crime. Q: St. Ignatius College Prep HS: Why are there such differing views among scientists that gene therapy or stem cells could cure Alzheimer’s disease? How can these opposing views be tested safely? A: Bob Nussbaum, M.D.: We do not understand why Alzheimer's disease develops or how to stop it from progressing, so it is hard to prove that introducing nervous system stem cells could have a beneficial effect. We also do not know at this point how to get stem cells to develop into fully functioning nerve cells that make all the billions and billions of connections that are needed for normal brain function. I would say that what all scientists do agree on is that we need to know more, research more, and understand more before we can even make an educated guess as to how likely it is that stem cells could treat Alzheimer's. Testing needs to be done by growing cells in a Petri dish to test basic questions about how stem cells become nerve cells as well as testing treatments in animals who have been made to develop Alzheimer's disease, like mice and (ultimately) monkeys. I also expect that some very brave and altruistic people with the disease will volunteer to be tested once the culture experiments and animal experiments seem promising. Q: eric. benjamin logan high school: is human DNA more complex than all or any other organism's DNA A: Kris Wetterstrand, M.S.: Yes and no. The human genome is more complex than the genomes of bacteria or insects. However, many other animal's genomes. One way in which the human genome is more complex than insects, is that each gene makes mulitple proteins. Q: Dan Walser!!! Vets HS Warwick RI: When you have sex is dna transfered in any way? A: Kris Wetterstrand, M.S.: Yes, in sexual reproduction, one copy of the genome, made up of DNA, comes from the mother and one from the father. Q: Garrett, Benjamin Logan High School, OH: How long will it be until we know the function of introns, and what do you predict their function will be? A: Eric Green, M.D., Ph.D.: EXCELLENT question. We are just starting to learn about possible functions for the sequences within introns. Previously, some thought introns did not necessarily contain functional sequences, but now we know that is not the case. For example, some introns contain 'switches' that influence when and where certain genes are turned on. There are certainly other important 'signals' within introns, which I predict we will discovery in the coming decade. The truth is that this represents an area of genomics that is NOT even described in the textbooks at your school yet. But stay tuned... Q: Ezra, Susquehanna Township HS, Harrisburg, PA: Is protein folding a topic to be addressed by the HGP? How so? A: Belen Hurle, Ph.D.: Good morning Ezra Good question. It is relatively complicated to determine the three dimensional structure of a given protein, but once it is determined it is much easier to predict the structure of other family members. the HGP has helped to discover and classify in families many, many novel genes . We can do computer modelling of these new proteins using as a reference the one structure that has been experimentally resolved. Q: Dr. Reinhart's Class, Newtown Square, PA: Is there any rhyme or reason to naming the four chemical bases? A: Kris Wetterstrand, M.S.: The four bases are adenine, thymine, guanine and cytosine, often represented as A, G, C and T. These names reflect the chemical structure of these bases. Q: St. Ignatius College Prep HS: How do scientists search for genes associated with certain human behaviors, (eating disorders, addiction, depression, attention deficit disorders, autism)? A: Bob Nussbaum, M.D.: We first need to figure out how "genetic" a particular disease is. We often do this by comparing twins in which either only one twin has the disease or both. Next, remember that each person differs at approximately 1 in 1000 bases of their 6 billion bases of DNA. To find the genetic basis for such diseases, we either study families or populations in which some people have the disease and some do not. We then compare the sequence of DNA in affected versus unaffected people, looking for differences in sequence that are consistently found in affected versus unaffected people. This kind of study, called "gene mapping", requires skills of being able to make careful diagnoses and observations, highly sophisticated laboratory studies and computer-based statistical analyses. Q: Kiran Belani, Montgomery Blair High School: Is there any part of your body that cannot be examined for DNA? A: Bob Nussbaum, M.D.: Your mature red blood cells and the cells of the lens of the eye do not have DNA - all the rest of the cells of the body contain DNA. Q: kelli: how does DNA tie into a career in forensic toxicology ? A: Eric Green, M.D., Ph.D.: DNA studies are quite important in forensics and increasingly in toxicology. Certainly, someone considering a career in these areas will want to become quite facile in the world of DNA and genetics. Q: Central HS, Helena AR: What made you so interested in science? A: Bob Nussbaum, M.D.: I was a trained doctor taking care of patients and became dissatisfied with the current state of knowledge in how to help my patients. I decided that only by becoming a research scientist could I push our level of knowledge higher rather than just applying what little we did know. Q: Kate, Ben Logan: What are somethings to expect as far as educating the public about genetics in the future? A: Kim Kaphingst, Sc.D.: This is an area in which NHGRI and others are doing a lot of work now. Researchers like me are studying how to help people learn about genetics. We also have educational programs for different groups to teach people information about genetics. You can find some of them at http://www.genome.gov/Education/ . This is an important topic and you're likely to see many more educational programs in the future. Q: steven WOOD, Warwick RI: Can we see DNA. A: Kris Wetterstrand, M.S.: DNA itself is too small to be seen with the naked eye. You can see certain types of pictures of chromosomes. Since the human genome has been 'sequenced' you can easily access and 'see' the genome at website such as that supported by the National Center for Biotechnology Information http://www.ncbi.nlm.nih.gov/Genomes/. Click on human on the right had side. Q: MEN: what is DNA? A: Kris Wetterstrand, M.S.: DNA is deoxyribonucleic acid. It is the chemical that makes up the human genome. Q: billy bob warwick ri: what is DNAs main job and why? A: Belen Hurle, Ph.D.: DNA is the molecule that stores the instructions to make you and every living organism. Is like your instruction manual that determines how tall you are, what is your eye color and so on. Q: Allan: We're 99.9% similar with each other. How can DNA change how we look with only .1% difference? A: Kris Wetterstrand, M.S.: THe human genome is 3 billion basses long. That give us 3 million differences at teh DNA level. That can lead to many differences in how we look. Q: St. Ignatius College Prep HS: How has awareness of various influences acting on the human genome, transposons, pseudogenes, repeat sequences, introns and intergenic DNA, epigenetic markers etc, influenced the direction of current genomic research? A: Eric Green, M.D., Ph.D.: Very good question. The things that you mention (e.g., epigenetic markers, transposons, repeats, and so forth) represent additional things that influence the functioning of DNA. Now that we have established the complete sequence of the human genome, attention is turning to how it encodes all of its information. Some of this is the primary sequence of its ~3 billion bases. But then there are other factors that play a role-- some of which you mention in your question. There are now ongoing efforts to study these areas in greater detail, with the goal of eventually unraveling all of the complexities of the human genome. Q: Central HS, Helena AR: Could genetic technology be used to create super-athletes? A: Bob Nussbaum, M.D.: I hate to say this but it is always possible to misuse scientific knowledge. I believe science is based on a desire to udnerstand - how we choose to USE this information is not purely a scientific issue but is one for all of society, citizens, government, religious leaders, etc. to address. So, COULD it be used - the answer is YES. We already know of at least one protein in the body, myostatin, that limits muscle size. In mice who lack myostatin and in one child who had mutations in his myostatin gene described this year in a medical journal, muscles are big and strong. So, if we somehow blocked myostatin function, we could make people have bigger, stronger muscles. I could see this being used to help people with muscle wasting because of cancer or muscular dystrophies or multiple sclerosis. I would HATE to see this used to generate super athletes - but I must say, I am not a big fan of professional athletics and wish the huge salaries paid to them were paid to high school teachers instead. Q: meghann warwick: what's the difference between DNA and RNA? A: Kris Wetterstrand, M.S.: DNA and RNA are different at the chemical level. In the cell DNA carries the ultimate copy of genetic information and RNA takes that information to make proteins. Q: Nate Stevens, Cape Elizabeth, ME: What are the positive and negative social implications of genomic discoveries? A: Kim Kaphingst, Sc.D.: There are many positive social implications of genomic discoveries. These discoveries will allow us to learn ways to treat diseases more effectively and prevent diseases from developing so that we can improve the public's health. It is important to make sure that we protect people's privacy and prevent discrimination based on someone's genetic makeup to avoid some of the possible negative social implications. Q: GO DNA, Warwick RI: What is the Human Genome? A: Kris Wetterstrand, M.S.: Genome is a word used to refer to the entire collection of genetic information that each cell in an organism carries. So, the human genome is the genetic information that we carry in each of our cells. It includes our genes (units that make proteins) and lots of additional information. Q: Chris: How would the various promoter sequences affect the genes of the human genome? Would they provide the same type of gene regulation the prokaryotic promoters do? A: Eric Green, M.D., Ph.D.: Promoters are sequences that act as 'switches' to turn genes on at specific times and in certain tissues or cells. Such regulatory control is critical for ensuring that the right genes are turned on (and the right proteins made) at appropriate times and places. Thus, promoters serve a critical role in orchestrating the expression and function of the ~25,000 human genes. Prokaryotic genomes have promoters as well, although they differ in a number of important ways. Because they are slightly simpler, at this point in time we actually know more about prokaryotic promoters than eukaryotic promoters. Hopefully, this will change in the coming years due to the ongoing work of genome scientists. Q: meghann warwick: how did you find the double helix in DNA? A: Aideen McInerney, M.S.: Watson and Crick, working with coworkers, discovered the double-helical structure of DNA in 1953. This work involved studying light patterns emerging from DNA-- which provided key clues about its structure.
Q: Eric, Newton North HS: How can genes program thoughts? (i.e., instincts, such as sexual preferences, or how cats know how to pounce on a mouse, whereas dogs are born knowing different things) A: Bob Nussbaum, M.D.: Great question and I can't answer it. We know VERY VERY little about how much one's instincts are programmed, "hard-wired" as it were. For example, black labradors love to swim and fetch - shepherds won't fetch and don't like swimming but they know how to herd. Labs can't herd to save their lives. We know there MUST be genetic differences that have been bred into these two breeds to select for these behaviours. As for sexual preference, we really know next to nothing about how this is determined. We know a lot about how genes program our basic sexual development, the internal and external equipment as it were, but very little about the higher, more abstract aspects of sexual behavior and identity. There are some scientists who are trying to find genetic variations that predispose to homosexual and heterosexual preferences...but it is not clear how much genes really control this difference. That said, this does NOT mean that sexual preference must be learned. There are other inborn determining factors (such as exposures before birth while in the womb or in early infancy) that could affect this, independent of one's genetic makeup. This is a very "hot topic" these days, with a lot of religious and political leaders arguing about the extent to which sexual preference is "learned", a "choice", versus how much it is innate, inborn, and not something that one chooses, but is something that one is born with. I do not think genetics has an answer to this puzzle. Q: Nick Geneva High School: How is dna tested? A: Bob Nussbaum, M.D.: We have methods for examining DNA in the laboratory and determing the exact sequence of the bases in any stretch of DNA. We can read the letters, A,C,G,T the same way you are R,E,A,D,I,N,G this message. Q: Dr. Reinhart's Class, Newtown Square, PA: Are favorite foods or behaviors genetically determined? A: Kim Kaphingst, Sc.D.: Right now researchers are studying how much of different behaviors might be determined by genetics. It's important to remember, though, that other factors - like friends, family, and how you grow up - play important roles in determining behavior. Your food preferences might have some genetic component but might also be affected by other things such as your culture and the things your family eats. Q: Joseph Dario from Montgomery Blair High School: Since DNA is structured to prevent mutations or modifications, how does the study of DNA support the theory of evolution? A: Eric Green, M.D., Ph.D.: Actually, DNA is mutated all the time-- indeed, every time you go out in the sun. But we also have repair mechanisms that correct most (but not all) changes. Studying the genome sequences of different species (an area called 'comparative genomics') reveals what has and has not changed (mutated) over millions of years of evolution. As we sequence more animals' genomes, fundamental knowledge about evolution is becoming refined and advanced. Q: Brandon Field, Vermont: What are the prospects for a career in the field of gene therapy research? A: Bob Nussbaum, M.D.: The field is wide open. We don't have dependable, safe ways of doing it, we don't know how to correct defects efficiently or effectively, how to deliver the therapeutic genes safely and efficiently, and that's just the beginning of the problems. So, for a smart, dedicated person interested in research and in treating sick people, the field "beckons". Hope you join in! Q: Samir: What kinds of genes does mitochondrial DNA contain? Could we survive without them? A: Eric Green, M.D., Ph.D.: Mitochondria have a several dozen genes, which have a number of different functions. We cannot survive without mitochondria. Indeed, mutations in mitochondrial genes are known to cause many different human diseases. Q: Billy Madison: How many years of education do you need to go into this field? A: Kim Kaphingst, Sc.D.: It is likely that you will need a graduate degree - and probably a doctoral degree - to be a researcher in genetics. So after college, you'd probably spend about 5 years in a doctoral program. This doesn't mean you'll be in classes for all those years, though - actually doing research is an important part of a graduate program. Q: Booker T. Washington MS, Baltimore, MD: In the future, will it be possible for HUMANS to transform into other animals via genetic engineering? A: Eric Green, M.D., Ph.D.: Unlikely. Minor changes to our genome-- maybe, such as with gene therapy. Major changes to transform us into other animals-- almost certainly not, biology is too complicated. Q: Lindsey, Benjamin Logan High School: Have you used any PCR in your research? Just wondering because we have. A: Belen Hurle, Ph.D.: PCR is the basic instrument in any molecular biology lab, and it is rare the day that you don't use it. PCR is like a photocopy machine. It allows you to make many, many copies of any tiny amount of DNA that maybe was too small to be analyzed before amplification. It only takes a few hours to generate thousands of copies from just a handful of DNA molecules! Q: Booker T. Washington MS, Baltimore, MD: What in your current research will be most important to future research? A: Eric Green, M.D., Ph.D.: Developing a catalog of all the functional sequences in the human genome. This will provide us the 'parts list' that will be a powerful resource for future genetics and genomics studies, including those aiming to establish how changes in our genome can cause human disease. Q: Reilly, Cape Elizabeth HS: Why is it so difficult to locate disorders in genes now that the human DNA has been totally decoded? A: Bob Nussbaum, M.D.: Good question! We may KNOW the DNA sequence but it has by no means been decoded! There is lots of information in DNA (sequences that REGULATE how genes are read and how the proteins are made, for example) that we don't know how to read or what it means - we only know in a few cases how changing this DNA sequence can increase susceptibility to certain diseases. Many genetic diseases are the complicated result of genetic variation AND environmental influences. Teasing out the genetic contributions from the environmental factors is hard!! We can think of this problem as a "signal to noise" problem. For diseases inherited according to Mendel's basic laws, we can locate genes easily because the defective gene has such a big effect, the "signal" is huge compared to the "noise" caused by other genes and environments. For example, we located the genes for Duchenne muscular dystrophy and cystic fibrosis many years ago. For the more common diseases that are the result of complex interactions, such as diabetes, schizophrenia, various cancers, some forms of mental retardation, the effect of any one gene on the disease is limited and therefore it is hard to see its signal in the noise. Q: j d: How many people have the same DNA? A: Kris Wetterstrand, M.S.: Only monozygotic (identical) twins have exactly the same DNA. However, on average, people are 99.9% the same at the DNA level.
Q: Fernando de Andres, Spain: How long do you think it will take to be able to save lives by fixing the DNA? A: Bob Nussbaum, M.D.: There have already been more than a dozen children with severe inherited immune defects that have been cured by gene therapy in which a defective gene was replaced. Unfortunately, three of these childen developed leukemia because the replacement gene got stuck into the middle of a gene that regulated the growth of the white blood cells that developed into leukemia. So, the therapy has been very succesful in over 10 children but three suffered a complication, one of whom died, the other two are in remission after treatment for their leukemias. Q: lloyd banks and da whole g-unit click: Why are gorrillas so close to humans and why are they so cool? A: Eric Green, M.D., Ph.D.: The sequence of our genome differs from that of the gorilla by only a few percent-- we are incredibly closely related to these remarkably cool creatures. I had the chance to visit the San Diego Zoo two weeks ago, and was given a behind-the-scenes tour of their gorilla exhibit. These animals have a very sophisticated way of communicating (through non-verbal means). Watching them for even a short period of time reveals numerous similarities with humans. Similarly, they suffer from many of the diseases as humans. Q: eric from ben logan high school: Do medicines actually correct a misspelling in the genome, or do they simply aid to the affects of the diseases through another method? A: Bob Nussbaum, M.D.: Medicines so far do NOT correct the misspellings. They affect biochemical and functional changes "downstream" from the gene itself. Q: Mark Nardelli Newton, MA: Is there an evil gene? A: Kim Kaphingst, Sc.D.: We don't think there is an "evil" gene. Behaviors that might be thought of as "evil," like committing violent crimes, are more likely to be determined by their environment, which means the way people grow up and influences from peers and family. Q: Karli, Benjamin Logan High School: What is an interesting unknown fact about DNA? A: Eric Green, M.D., Ph.D.: A fact that is now 'known' but a surprise that emerged a few years ago... The human genome does not even have TWICE the number of genes as the fruit fly genome--- yet seemingly we are more than twice as complex. Go figure! Q: Megan, Benjamin Logan: How would they go in and change the sequence of DNA so diabilitating diseases weren't present in the human fetus? A: Bob Nussbaum, M.D.: We do not know how to do this efficiently and effectively yet. There are methods for replacing defective information in cells being grown in Petri dishes but it is very inefficient and only works in 1 in a few thousands to a few millions of cells. We can also inject a normal gene to replace a defective one but it does not "home in" to the actual defective gene and cut it out and replace it with a normal copy. Q: Frannie, Waubonsie hs in Aurora, IL: Does our DNA change as we age because of viruses we might acquire in our lifetime? A: Bob Nussbaum, M.D.: DNA does change as we age but not primarily due to viruses. DNA is a chemical and it suffers "wear and tear" from toxic chemicals. Also, as the cell copies its DNA, there is a basic level of "typographical error" that occurs, so DNA can accumulate typos. Q: Danno Cox, Ohio: What is a plasmid? A: Kris Wetterstrand, M.S.: A plasmid is a structure in cells consisting of DNA that can exist and replicate independently of the chromosomes. Q: Dr. Reinhart's Class, Newtown Square, PA: How long is DNA viable for identification or experimentation in any sort of preserved state like cryogenic freezing or the like? A: Bob Nussbaum, M.D.: VERY long time. we have cells that have been frozen away 40 years ago that have been brought out of deep freeze and can grow on Petri dishes in culture. If the DNA is actually purified and stored in solution, we don't know how long DNA could be preserved. A scientist called Svente Paabo isolated DNA from the teeth and bones of a Neandertal man. There was also that caveman found frozen in the Alps from whom I suspect DNA could be successfully isolated. Q: Kiran Belani, Montgomery Blair High School: How does the cell distinguish between the exons and introns in the DNA when creating mRNA? A: Eric Green, M.D., Ph.D.: The process of forming the final mRNA molecule is called 'splicing'. Embedded within the DNA sequence are signals that tell the splicing machinery where to cut out introns, leaving behind the exons. While we know quite a bit about these signals, we have much more to learn-- especially since the same gene can lead to multiple different forms of mRNA. What are the signals that determine which forms are made at different times and in different cells? These are the kind of questions being addressed now in genomics. We hope to establish a complete catalog of such signals in the human genome. Q: Domenica: When I have a child when I get older, will my child recieve most of my "husband's" traits? A: Bob Nussbaum, M.D.: Every child gets half of his genetic info from his Mom, half from his Dad. Which half of his Dad's genes and which half of his Mom's gene the child inherits is entirely up to chance, 50-50, like flipping a coin. So, will the child receive most of your husband's traits? No, each child will get half of his genetic info from his Dad, but the relationship between information and traits is unpredictable. NOT all traits are strictly genetic and some are the result of combinations of various genes - if you get some of these genes but not others from a parent, will you also have the trait? or not? Tough question and we don't have an answer.
Q: pAT pAT, Ben Logan HS: if twins have the exact same DNA, if one is a suspect in a murder case how could you determine which one comitted the crime using genetics? A: Jean McEwen, J.D., Ph.D.: The law enforcement officials investigating the case would need to look at all the evidence together - the DNA is just one piece of evidence. So they would try to find additional evidence, beyond just the DNA, that tied one of the twins to the crime, or establish that the other twin had an alibi (i.e., was somewhere else at the time and could not have committed the crime). In the end, the DNA would be just one piece of evidence in the case that the court or the jury would consider. To my knowledge, there has not yet been a case in the U.S. involving a dispute over which of two twins committed a crime, where the DNA evidence showed that it could have been either of them. Q: Kyle Dancause, Cape Elizabeth Maine: How can the chihuahua belong to the same species as the great dane? A: Heidi Parker, Ph.D.: The domestic dog, Canis familiaris, is a single species that diverged from the Gray Wolf somewhere between 15,000 and 50,000 years ago. All of the breeds that we see today are the result of specialized breeding programs developed by humans to create animals that fit a specific need. Even though dogs like the Great Dane and Chihuahua look very different today, their ancestors came from the same family. Q: St. Ignatius College Prep HS: How might RNA’s antisense abilities support the hypothesis that RNA was the original hereditary material? A: Eric Green, M.D., Ph.D.: A very sophisticated question. The more we learn about RNA and the ways it can confer function, we gain clues about how RNA may have played a central role in early life forms. You raise an interesting question about some newly discovered ways that antisense RNA controls the expression of genes. What were the evolutionary origins of antisense RNA? Perhaps this points to an earlier role where RNA played a more central role in biological function, perhaps even predating DNA's role. Q: Dr. Reinhart's Class, Newtown Square, PA: Is any one chromosome more susceptable to mutation than the others in human beings? A: Bob Nussbaum, M.D.: Over what time frame? From generation to generation, no, mutation is pretty much the same across all chromosomes. Over evolutionary time, hundreds of MILLIONS of years, the Y chromosome seems to be changing more rapidly by losing information that is going to other chromosomes. Also, the ~16,500 basepairs of mitochondrial DNA has a higher overall mutation rate than the 46 chromosomes in the nucleus. Q: Ms. DeVito: Has a human been cloned yet? Our clas is wondering what the latest news is? Thanks. A: Eric Green, M.D., Ph.D.: No human has ever been cloned, at least as far we know. There are certainly no plans at the NIH to clone a human. This topic is often discussed in a casual way-- in reality cloning a human would be technically difficult and likely quite dangerous. There are many biological aspects to this process that we do not yet understand. Q: Jisung Kim, Montgomery Blair High School: Is there a hypothesis theorizing if chloroplasts were once their own separate cells and how they became part of plant cells? A: Belen Hurle, Ph.D.: Endosymbiosis is a symbiotic relationship between two organisms in which one of the organisms lives inside the other.Almost all biologists believe that this phenomenon explains where mitochondria and chloroplasts came from. In the early stages od life, not all organisms developed the ability to perform photosynthesis, or to convert to aerobic cellular respiration. Many of those that didn't make these alterations themselves went into partnership with other organisms that did. If an anaerobic cell could engulf an aerobic one (without digesting it), it could get the benefit of the ATP overflow from its captive partner. Given a couple of billion years to get used to each other, the inside, aerobic partner became so specialized for aerobic cellular respiration that it lost almost all of the basic life skills, depending upon the external host cell to support it. Voila` – mitochondrion. If you tell the same story, but substitute "photosynthesis" for "aerobic cellular respiration," you have a recipe for the invention of chloroplasts. Q: Drake: My dog Bear looks different then his brother Colby? Why does this occur and do genetic mutations on the #22 chromosome cause this? A: Heidi Parker, Ph.D.: Your dogs look different because they each have a unique pattern of genes and mutations that affect appearance. Even though they both got their looks from their parents, they received a different mixture of features which gives them their own individual look. Mutations that cause these differences can be found on any or all of the dog chromosomes included but not limited to chromosome 22. Q: Billy Madison: What is gene therapy? A: Donna Krasnewich, M.D., Ph.D.: Gene therapy is a way to treat some genetic disorders which currently is being done in a research setting. An example may be the best way to explain how it works. Some children/adults have alterations in their DNA that makes their white blood cells ineffective in fighting off infections in their body (ie. severe combined immunodeficiency disease). Gene therapy for this disorder would be to remove some of the precursor white blood cells (the "mother" cells) from the bone marrow of the affected child. Then these cells are taken to a very sterile laboratory and the cells are incubated with the corrected gene that these cells are missing. Some of these precursor cells "take up" the gene and actually integrate it into their genome. It is then replicated like the cell's own DNA. Then these cells are taken from the sterile laboratory and given back to the patient by an intravenous transfusion. Hopefully, these mother cells will produce "corrected" cells that will move into the blood stream and help that person fight off infection. Remember, gene therapy does not work, at this time, for all diseases because the gene must be able to get into cells where it is needed. Some organs are harder to move corrected genes into, ie the brain. Researchers are working on strategies to widen the spectrum of diseases that will be helped by gene therapy. Q: Candice Josphinum High School: Is it true that, in the future, everyone will have to get an DNA test when they are first born? A: Jean McEwen, J.D., Ph.D.: Already today, virtually every baby born in a hospital in the U.S. gets blood drawn through a heel stick. This blood is then tested for a variety of inherited childhood disorders (such as PKU, or phenylketonuria). This testing, called newborn screening, is mandatory in most states in the country. In most states, the blood spots from these tests are saved onto cards, which are stored for many years, and in some cases indefinitely. So, the blood spots on these cards could theoretically be looked at in the future, if somebody wanted to do DNA testing. Of course, most states have laws that limit who has access to these cards and what they can be used for. But some privacy advocates are worried that these laws are not strong enough. Q: Alexis Rensselaer: what is genetics A: Heidi Parker, Ph.D.: Genetics is the study of genes. Although these days geneticists do not limit themselves only to genes but study all regions of the chromosome, and sometimes elements that interact with chromosomes, that can be inherited. Q: Jared Barnes, Ben Logan: What possible restrictions on health care and insurance will we see in the near future as a consequence to DNA mapping? A: Jean McEwen, J.D., Ph.D.: Nobody really knows for sure. There have already been some reported cases of people being denied health insurance (or charged really high rates for insurance) because they have a gene that predisposes them to get a certain disease. Some people worry that this kind of "genetic discrimination" will happen more and more in the future, as more and more genetic tests become available. Some states have passed laws that limit the extent to which insurance companies can take genetic information into account in issuing insurance policies. However, these laws vary a lot from state to state. So a lot of people think that federal legislation is needed in this area. So far, however, no federal legislation has been enacted that prohibits genetic discrimination in insurance. Q: Karla - Benjamin Logan HS: Could paralysis be caused by some misspelling of DNA? A: Donna Krasnewich, M.D., Ph.D.: There is DNA that codes for each and every part and function of our body. So, there are genes that code for the way all of the nerves and muscles that work together to help us move. Paralysis is the inability for a person to move their muscles/parts when they want to. They may have a problem with the way their brain is sending the signal, the nerves that take that signal to the muscle or the way the muscle moves in response to the nerve impulse. There are many genes that code for these parts and an alteration in one of them may lead to "paralysis" of difficulty moving a part of their body. Sometimes a child has a problem moving their body when they are born. This is called a congenital problem. Sometimes people have paralysis come on when they are older. This was always coded into their DNA but the onset of their problems were not programmed to start until they were older. Many physicians will be able to help answer more specific questions. Q: boby dumb: Are twins identical genetically? A: Belen Hurle, Ph.D.: There are two kinds of twins: identical twins and fraternal twins. If the mother produces 2 eggs during the same cycle instead of one egg only, and both egges are fertilized, you have fraternal twins. Fraternal twins are not any more similar than normal sibilings. Identical twins happen when a fertilized egg splits in half during the early stages of embryo development. Identical twins are identical at the genetic level. Q: Sarina Taylor: How similar are the dog and human genome (to what degree)? A: Heidi Parker, Ph.D.: The genetic content of the dog and human genomes match at approximately 70-75% over all. Regions that are translated into proteins are typically greater than 90% identical.
Q: Eli, Cape Elizabeth, Maine: I'm currently researching Asperger Syndrome for a genetic disorder and I was wondering if there was a chromosome mutation causing it. A: Donna Krasnewich, M.D., Ph.D.: As you know there is alot of work currently being done to understand why children have Asperger Syndrome. You also know that there are hypothsized causes including genetics changes, environmental triggers and combinations of genes and environment. There is a very nice review of the topic of autism including asperger syndrome with the genetics causes listed on www.genetests.org. This is very useful resource written by experts to explain some genetic disorders. Q: Sarina Taylor, New Jersey: why do older dogs tend to develope moles and sometimes even tumors? A: Heidi Parker, Ph.D.: Tumors are groups of cells that are growing without the usual cellular controls often due to aquired mutations within the cells. Every time a cell divides it has the opportunity to acquire a mutation. As with humans, dogs are more likely to develop tumors as they age. The older the dog, the more time it has had to build up mutations that lead to tumor formation and sometimes cancer. Q: Lesley Greenville, AL: Do you think cloning humans will ever be legal in the United States? A: Jean McEwen, J.D., Ph.D.: Maybe, but probably not for a very, very long time - if ever. Right now, human reproductive cloning just has not been demonstrated to be possible. Even if it became possible, there would be very serious physical safety risks associated with human reproductive cloning, so it would be extremely dangerous to attempt. For this reason, and because of the very serious ethical issues raised by human reproductive cloning, this practice will almost certainly not be allowed under the law for a very long time, if ever. Q: billy bob, fort deposit: how different is my dog and my chromosomes A: Heidi Parker, Ph.D.: You have 22 pairs of chromosomes and an X and Y chromosome. Your dog has 39 pairs of chromosomes if it is a girl or 38 pairs and an X and Y if it is a boy. Q: Central HS, Helena AR: I feel that some of the genetic technologies are beneficial, but we as people are getting a little outrageous. I feel that some of these decisions should be made only for medical attention. We are playing with people’s lives. Do you think there is a need for god? A: Colleen McBride, Ph.D.: You raise an important concern and one that our Institute has made a priority. Indeed, in applying genomic discovery the social impact of these developments should be taken into consideration. For that reason, we have an active program of research and advisement in the ethical, social and legal implications of application of genetic technologies. Q: Sarina Taylor, Ridgewood HS: what organism has the most chromosomes? A: Belen Hurle, Ph.D.: I don't know which organism has the record, but is probably a plant. Angiosperm plants have polyploid genomes which means that the whole genome is in multiple copies. I will give you some examples: humans have 46 chromosomes (2n, diploid genome); sugar cane has 80 chromosomes (8n) ; species of coffee plant with 22, 44, 66, and 88 chromosomes are known (2n, 4n, 6n and 8n respectively). Q: Candice Josephinum High School: How can someone who has never met their parents trace back their DNA to find out who their parents are? A: Donna Krasnewich, M.D., Ph.D.: For many this is a topic that can be very emotional, bringing out both happy and sad feelings. The technical answer is that there are DNA tests that will verify that a person is a parent if that parent's blood is available to compare. However, currently there is not a databank of DNA from every person (remember all of our DNA is different and individual) so a match may not be available leaving the person asking the question without an answer. There are people who are experts in answering these questions for an individual, they are called geneticists/genetic counselors, usually they are at medical centers in many cities. They may be help a person sort through the options available, the cost and the emotional issues surrounding this question. Q: Ann, BLHS: Could you please explain ELSI? A: Jean McEwen, J.D., Ph.D.: NHGRI allocates 5% of its total budget for genomic research to the support of research on the ethical, legal, and social implications (ELSI) of that research. The idea is to try to anticipate and address some of the major ethical, legal, and social implications raised by this type of research before problems arise (e.g., issues about privacy, genetic discrimination, how genetic information will be used in health care, intellectual property issues, etc.) For more information on ELSI, please visit: http://www.genome.gov/10001618 . Q: Elezar ,Hyderabad, india: Why do some scientists call centromeres the "black holes" of chromosomes and what is their function? A: Heidi Parker, Ph.D.: Centromeres are the sites on the chromosomes where the cell division apparatus attatch in order to pull the two matching chromosomes apart when the cell divides. The region is difficult to sequence through because of its physical structure and the presence of repetitive DNA sequence. There are no active genes known to be in the centromere region of the chromosomes which may lead to discriptions such as the "black hole" Q: Annie, BLHS: What are some the future projects that will branch off of the HGP? A: Larry Thompson: Sequencing the human genome was just the first step of this amazing journey to understand all the parts that make up the human body. The HGP is rapdily leading to identifying all the genes in the body, as well as the regulatory pathways that tell genes when to turn on and how to interact with other genes. The National Human Genome Research Institute has launched a number of sophsiticated studies to help interpret the genome, including the International HapMap Project, which is designed to detect and understand the common variation in the human genome; the ENCODE project, which is designed to detect every kind of information and control mechanism in the genome; the chemical genomics program, which is identifying small molecules and creating a screening program to probe gene function and understand the biological networks, and which may also lead to the development of new medications. There are many other initiatives, such as those in nanotechnology, a project to make strains of mice in which individual genes are knocked out, so the genes function can be studied, and a series of ongoing studies to understand the ethical, social and legal implications of all this new knowledge. Q: Jason Machamer, Susquehanna Township: What tests did you do to find out DNA is six feet long? A: Larry Thompson: That's a great question, because it certainly is hard to imagine how something that long can be packed into a cell so small that you can't even see it. The genome length is estimated to be six feet long by physically measuring the molecules that make up a nucleotide and then adding up the estimated amount of DNA in each individual chromosome. So, while it is very long, a strand of DNA is extremely thin -- way thinner than hair. Q: Sarina Taylor: Would it ever be possible for a doctor to literally change someone's DNA in order to cure genetic diseases? A: Donna Krasnewich, M.D., Ph.D.: Gene therapy is the way to do this. Currently, gene therapy is in the research phase and scientists and physicians are working hard to find ways to integrate genes into DNA that work better. This may either just help make someone feel better or cure the disease. There is alot more work to do on this front. Q: Sydnie Hill, Tulsa, OK: How can pet owners prevent their dogs from having cancer? A: Heidi Parker, Ph.D.: Cancer in dogs is similar to cancer in humans. You can prevent your dogs exposure to possible cancer causing agents like smoke or pesticides but if your dog has inherited the predisposition to cancer there are no preventative methods known to stop it. The best thing to do is to try to catch the cancer early so that the dog can get proper treatment and improve their chance of survival. Q: Sarina Taylor: Are any breeds of dogs more similar as far as DNA to humans then other breeds? A: Heidi Parker, Ph.D.: No, all the breeds are more similar to each other than they are to any other species. Q: Mark Nardelli's class, Newton, MA: Are there genes for violent behavior? A: Colleen McBride, Ph.D.: At this time, there is no gene to explain violent behavior and it is unlikely that any single gene will explain such a complex behavior. Scientists agree that unraveling the factors that explain behaviors such as aggression and hostility will be a very complicated undertaking because it will involve the combination of multiple genes and environmental influences. The research is ongoing. Q: St. Ignatius College Prep HS: Would you spend the money to save your own child’s umbilical cord stem cells as a future insurance policy? A: Don Hadley, M.S., C.G.C.: This is a sensitive question for many people. It is clear that stem cells from cord blood have the potential to be very helpful in some clinical situations...certainly this is a field that will advance in the coming years. Q: Katie, Chicago: why does that kid keep asking about his dog? A: Larry Thompson: I suspect we are getting a lot of dog questions because some students are watching the multimedia webcast in which our cancer branch chief Elaine Ostrander, Ph.D., discusses her genomic research with dogs. If you are interested in learning about Dr. Ostrander's dog research, you can see the webcast at http://genome.gov/14514276. Q: Schumm's Genetics Class: We've just read about Alu repeats, a major class of SINEs. Our information states that each repeat is about 300 bases long and comprise about 2 - 3% of the genome & are increasing. Do you know what they do yet? At what rate are they increasing? How will that impact our genome? A: Belen Hurle, Ph.D.: Our genome is littered with all kinds of repetitive elements, and Alu repeats are one family of many. These elements have the capacity of replicate themselves and integrate in different places of the genome.Per se they don't add or substract any function to our genomes. In an indirect way, they are thought to increase the number of non-important targets of mutagenic agents, in other words they "dilute" the number of mutations that could impact important genes. They also promote genome plasticity and speciation during evolution , because they promote non-homologus recombination and genomic rearrangements. On the dark side, they can cause genome inestability and chromosome fragility with the result of human genomic syndromes (a piece of cromosome gets deleted or moved to a wrong location of the genome). Q: Ted Bundy from Berlington Vermont: Is it possible to steal peoples DNA? A: Jean McEwen, J.D., Ph.D.: Yes, theoretically, all you would need to do is to obtain a strand of that person's hair, some saliva (e.g., from a cigarette butt), or some scrapings from their fingernails. But, of course, just having the strand of hair, the saliva, or the fingernail scrapings would not automatically tell you anything about that person's DNA; in order to find out the information encoded in their DNA, you would need to subject the person's sample to DNA analysis This would require specialized knowledge and laboratory equipment.
Q: Sarina Taylor: i remeber reading about a family who had their older dog cloned so they could still have that dog after it passed away. Would these clones just look the same or would they have the same personality as well? A: Heidi Parker, Ph.D.: While there are some aspects of behavior that may be genetically controlled, personality is probably due more to the environment that the dog was brough up in. Since the field is extremely new, there have not been any studies to compare clone personalities to the originals. Q: Eduardo Caroacheo: Are their any chemicals that can alter your DNA? A: Donna Krasnewich, M.D., Ph.D.: There are chemicals called mutagens or teratogens that may change the physical nature of the DNA. Remember that much of the time these chemicals work in a random manner, this means that it may not affect a gene that makes a change in the physical appearance of any individual. Q: Dr. Reinhart's Class, Newtown Square, PA: Why did you choose April 25 as DNA Day? A: Colleen McBride, Ph.D.: April 25 is an important day for the National Human Genome Research Institute. It was the day that the final sequence of the human genome was published. Additionally, April was the month in 1953 during which Watson and Crick first described the structure of DNA.
Q: Bobby Jo, Greenbo, AL: Does every mammal have the same DNA? A: Heidi Parker, Ph.D.: Every mammal has the same set of basic genes needed to live and replicate. They do not have the exact same DNA and the genes tend to be rearranged and the seqeunces slightly different. This accounts for the differences seen between the species. Q: Ben Henig, Susquehanna Township High School: If you know the sequence of DNA of a gene that causes a disease, how does that help in the creation of a treatment for the disease? A: Donna Krasnewich, M.D., Ph.D.: You are asking an excellant questions that is the basis of work in many labs. First, once you know the sequence of DNA then you have to find out what protein the DNA codes for. Then one has to learn how that protein functions, which will help to explain why a dysfunction of that protein causes disease. Now you have narrowed down where to focus the therapy which can either be a biochemical intervention or perhaps an interaction with some physiologic process. There are also currently some innovative work being done on strategies to design a therapy that DNA or RNA interacts directly with other genetic material to change the disease course. This is very new and still in the laboratory phase. Q: Jbarnes: Is there any current research pertaining to a bacteria genome and antibiotic/antimicrobial resistance? A: Belen Hurle, Ph.D.: Yes a lot. Many bacteria strands that cause serious disease, such as tuberculosis, have develop resistance to antibiotic treatments which is a serious medical concern. Other researchers study the genomes of bacteria that do not cause disease, such as the normal flora in our gut, or our mouth.
Q: Randi, Benjamin Logan High School: so far what's happened in the knockout mouse project? A: John Hodges, M.S.: The Knockout Mouse Project (KOMP) is still in the planning stages. At the end of March NIH held a workshop which solicited advice from the larger scientific research comunity about how to go forward with the project. The NIH KOMP working group is now evaluating the recommendations from the meeting and articulating a funding plan to get the project going. Q: Erin A, Susquehanna Township HS, Harrisburg, PA: How important to the medical field is protein folding? A: Belen Hurle, Ph.D.: Very important. Many point mutations alter the normal folding of a protein imparing its physiological function and causing lethal or very serious conditions. Sometimes, just learning about the folding of an unknown protein gives important clues on its function (is it a pore-like protein? does it look like a channel or a transporter? is it soluble?) . Q: Wawasee High School: If we inherit mitochondria from our mother, shouldn't we have the same metabolism as our mother? A: Donna Krasnewich, M.D., Ph.D.: Metabolism is controlled by many factors within our body besides our mitochondria. Specifically within cells there are other metabolic pathways including how we break down fats and sugars or how we respond to glucose in our bodies. The number of variables that may influence our physiologic metabolism is large and many genes, both from our mother and father influence that metabolism. Q: Eric, Newton North HS: How do genes create complex shapes? (Such as bones or the circulatory system) A: Heidi Parker, Ph.D.: Typically a gene is a sequence of DNA that is translated into a protein. These protiens then have various roles in the cell that can establish the cell type during the early stages of development. The types of genes that are expressed, the amount of protien produced and the timing of the protien production creates specific cell types such as a bone cell or blood cell. Q: Selitta, Rockingham NC, but live High Point at T.Wingte Andrews High !Go Red and Richmond Raiders!: When do you expect the Genome project to be complete? A: Larry Thompson: The Human Genome Project was officially launched in October 1990, and it was expected to take 15 years. The first draft of the human genome was announced in June 2000 and the final human genome sequence was placed in the public databases in April 2003, at which point the Human Genome Project was completed. Genome studies continue, however, to understand all the information contained in the genome sequence. Q: Emily Bean, Queensbury, NY: Does DNA affect ear wax color? A: Donna Krasnewich, M.D., Ph.D.: There is a specific disease called alkaptonuria which can affect a person by giving them dark urine, cartilage and even darkened ear wax. Alkaptonuria is a metabolic disease that changes the way an individual uses specific amino acids and creates a buildup of a certain chemical which is black in color. People with alkaptonuria also may have significant joint problems. If someone has very dark ear wax I would suggest that they see their physician to be evaluated. Q: Zeba Race, Newton, MA: Do you ever get tired of working in a lab with things that are smaller then you can see without a microscope? A: Belen Hurle, Ph.D.: Not really. It is like peaking through a window to other worlds. I think that astronomers looking through a telescope feel the same kind of excitement. The most frustrating part of research is that it requires a lot of patience. Sometimes you go for a long period of time without discovering anything relevant and you feel miserable, sometimes you make several exciting discoveries in a row and you feel very good about yourself. Q: Ryan Gustafson, Chicago: When diagnosing behavioral "disorders" isn't it somewhat misleading to call these disease? How much of a continuum exists in terms of the severity of behavioral disorders? A: Colleen McBride, Ph.D.: Yes, I would agree that in many cases referring to variation in behavior as disorders or diseases might not be appropriate. In many genetically influenced characteristics there is a continuum or degree of expression that influences the "severity" of the phenotype. What we classify as a behavioral disorder also is influenced by what society defines as normal behavior, that in turn can be changed by social forces. So your point demonstrates the complexity of this issue! Q: Sadako Yeol, Japan: Is there genetic information in tumors? A: Donna Krasnewich, M.D., Ph.D.: Tumors, which are the solid form of cancer, have DNA within the cells that compose them. This DNA has changes in it that cause the cells within the tumor to grow without stopping when they touch another cell. This uncontrollable growth causes solid tumors. Q: Sarina Taylor, Ridgewood HS: Is it ever possible for two people or organisms unrelated, to have to same dna coinccedentally? A: Heidi Parker, Ph.D.: Statistically it is impossible. That would require two random people to match 3 billion bases with 4 possibilities at each base. Q: Regine, Chicago: Can scientists use DNA to bring back the dinosaurs? A: Larry Thompson: Your question, of course, was the thesis of the book and film, Jurassic Park. While anything is possible, scientists are far from being able to technically do in reality what the film-makers could do on the silver screen. However, scientists have isolated DNA from extinct animals. California scientists isolated genes in the early 1980s from a quagga, an extint animal that looks like a cross between a horse and zebra. The genes came from a small clump of dried muscle tissue found in a museum display with a quagga in it. Still, it's hard to imagine that a dinosaur could be brought back to life because DNA extracted from these ancient samples tends to be broken up pretty badly and are unlikely to be functional. Q: Charlitta,High point NC: Why is DNA damaged by ultraviolet rays? A: John Hodges, M.S.: UV Radiation damages DNA through a variety of different mechanisms: 1) UVA raditation generates Reactive Oxygen Species (ROS), or free radicals, which react with and damage DNA. 2) 8-Oxoguanine, which also results from exposure to UV radiation, leads to GC --> AT transitions by mispairing with adenine. 3) UV radiation also produces thymidine dimers and single strand breaks. Tymidine dimers result when there are two adjacent "Ts" in the DNA sequence which become joined with a covalent bond. Q: Sarina Taylor, Ridgewood HS: Is being albino caused from a mutation? if so why does this mutation seemingly occur so often? A: Donna Krasnewich, M.D., Ph.D.: Albinism is lack of pigmentary material in the cells where it belongs. Pigmentary material has color. There are many different conditions where either the pigmentary material isn't made correctly or isn't put in the right place in the cell so that the cells collectively do not have pigment....thus the individuals are albino. Albino individuals occur in many species, I suspect because of the same mechanisms I mentioned above. It is interesting that you think they are common, the numbers show that they may be as rare as 1 in 40000 to 1 in 60000 individuals. Thanks for your questions. Q: Sarina Taylor, New Jersey: Are their any ways to prevent genetic diseases before a baby is born? A: Jean Jenkins, R.N., Ph.D.: That's a really good question. Prevention is not always on the minds of persons considering having children! A good first step to thinking if a couple is at risk of having a child with a genetic disease is to go back to family history. Talk with relatives about any history of problems of genetic conditions in the family. Ethnicity is also important to consider as some conditions occur more frequently with certain ethnic origins. Such factors may indicate the potential for higher risk factors that may be inherited in the family or affect pregnancy. If there are concerns raised, there are genetic counselors who can help assess the risk further and discuss implications for the pregnancy. Personal characterisitics also influence the health of the baby - for instance, women who are older have a higher risk of having a child with Downs syndrome. So consideration of age, medications, and environmental exposures are all important to consider when thinking about having a healthy child. Healthy lifestyles are also important for prevention - such as adequate folic acid intake, and no smoking or alchohol during pregnancy. For the future, gene therapy as an option for intervention in utero is being considered. Clinical studies will be needed to determine the effectiveness and safety of correcting a genetic disease in utero. Q: Booker T. Washington MS, Baltimore, MD: Is there a genetic path to finding a cure for AIDS? A: Donna Krasnewich, M.D., Ph.D.: This is a very important and complex question. There are alot of people working on understanding why some people are more resistant to contracting the clinical symptoms of AIDS dispite exposure to the virus. There are many labs working on genetic strategies from a variety of angles to design new therapeutic strategies. Q: Ashley, T Wingate Andrews: What is the Knockout Mouse Project and the Minority Plan? A: John Hodges, M.S.: The Knockout Mouse Project (KOMP) is a Trans NIH project to generate a comprehensive catalog of null mutations in ES cells for every gene in the mouse genome. These would be made readily available to all researchers at a low cost. The Minority Action Plan is a NHGRI specific initiative which requires grantees to insitute programs aimed at recruiting underrepresented minority students into academic careers in the genomic sciences. Q: Caitlin, Chicago: Why do mature red blood cells and the cells of the lense of the eye not have DNA? A: Belen Hurle, Ph.D.: Because they are highly specialized cells. Red blood start out with a nucleus, like other cells, but when they fill up with hemoglobin the nucleus is squished smaller and smaller until it disappears. With no nucleus, red blood cells are fragile and live only about 120 days. In your body, about 2 million red blood cells die per second! But your bone marrow produces new ones just as fast. The lens fibers are highly elongated, thin, flattened structures without nuclei and other organelles. They are filled with proteins - crystallins Q: Andrea Hyatt- Campbell....4ever & always: Does DNA affect the size of your body and how? A: Heidi Parker, Ph.D.: Yes, there are genes that effect the speed at which you grow, the length of time that your body continues to grow (and when it tops growning), the density of bones, the size of your head etc. Some of these genes work together. These are often called quantitative genes and the effects can be added together to give variations in size. There are also mutations in genes that cause extremes of size in rare cases. Q: Jordan Hawley, Tulsa, OK: Is being a midget hereditary? A: Donna Krasnewich, M.D., Ph.D.: First, the word midget is not the right clinical word for individuals who have short stature, the correct word is dwarfism. There are many genetic causes of dwarfism with the most common being achondroplasia which is inherited in a dominant pattern from one parent or the other. This gene is called FGFR3. Q: Mary Kate Franchetti, Columbia MD: If I was interested in studying Biology in college, and possibly become a biologist, what might be the best way to experience the field, hands on, as a high school student? A: Belen Hurle, Ph.D.: Hi Mary Kate, I see that you are in Columbia MD. I ENCOURAGE you to apply to a summer research program at the NIH or any university around here. You will spend 8 to 10 weeks in a laboratory, working on your own research project and learning about what other researchers in the lab do. It is a great way to find out if you really like research and it also will look very good in your college application. For research opportunities at the NHGRI check out http://www.genome.gov/10000218 Q: justin, high point nc: Is the cheek Swab test a possibility or merely hypothetical? A: Jean Jenkins, R.N., Ph.D.: Use of a cheek swab for genetic testing is already being used as a genetic testing methodology. As with any genetic testing, quality control of the laboratory processing the sample is important to consider. The main concern with genetic testing is that individuals are informed about the risks and benefits of what the test result information wil provide. Sometimes use of cheek swab testing bypasses such genetic counseling. Q: Amy Tai, Newton MA: Is it possible to take apart DNA and rearrange it to form a different gene? A: John Hodges, M.S.: The short answer is, 'yes'. This can happen on a couple of different levels. Meiotic recombination occurs in Meiosis and is responsible for generating a significant portion of the genetic diversity that fules evolution. Essentially, large pieces of sister chromosomes swap places and this sometimes leads to the combination of new genetic elements creating a new gene or changing expression levels of that gene. It is also possible to manipulate genes and other pieces of DNA in the laboratory. Researchers, using a host of different enzymes and other technologies, can isolate different pieces of DNA, change them, and piece them back to together again. This is called molecular biology. Q: St. Ignatius College Prep: How do scientists go about searching for genes associated with certain human behaviors? Do these behavioral genetics studies hold any water with the molecular biologists? Would you consider these really separate disiplines or are they examples of any serious research efforts with an intergrated approach? A: Don Hadley, M.S., C.G.C.: Identifying genes asociated with human behavior utilize the same basic approaches as those used for identifying more medically focused diseases such as Huntington disease or Cystic Fibrosis. Therefore, the approaches used are not questioned. Behavioral conditions challenge scientists to begin to develop approaches that are able to consider the contributions of more than one gene as well as contributions from the enviroment. From that standpoint, molecular biologists are watching the efforts of those studying human behavior closely since they are beginning to be asked to address common medical conditions that have "complex" (both genetic and environmental) causes. In summary, I see them as complementary approaches that will mutually benefit each other. Q: Matt Morrone - Harrisburg: How does reverse transcriptase work? Why is it necessary in cells? A: Heidi Parker, Ph.D.: Reverse transcriptase creates DNA from RNA. It is not a component of a cell, but comes from RNA viruses that use it in order to create DNA so that they can transcribe their own viral protiens after they enter a cell.
Q: JT, T Wingate Andrews: Is there DNA present in your body after you die? A: John Hodges, M.S.: Yes, DNA exists in our cells after we die. Q: Charlotte Ahearn, Baltimore Maryland: How does one create a genetic map? A: Belen Hurle, Ph.D.: It depends: if it is a physical map, normally you start creating a restriction map, that is chopping the original DNA in a controlled way into pieces with the help of a collection of restriction enzymes . Then you put together the DNA fragments like pieces of a puzzle. If it is a genetic map, say in mouse, it involves crossing mice from two mouse strains and following up how a collection of genetic markers that span your region of interest segregate in the offspring. Q: Peter O'Hagan, wellesley ON: Is RNA generated during transcription from the DNA, or is there a molecule already present that receives the copy of the DNA and thus becomes mRNA? A: Heidi Parker, Ph.D.: RNA is generated during transcription from individual nucleotides available in the nucleus. Transcriptional proteins take the nucleotides and connect them together in a particular sequence matching the DNA sequence that is being read. Q: TJ High Point, NC: Can you trace Autism or other mental illnesses within family bloodlines? A: Jean Jenkins, R.N., Ph.D.: There is a lot of research ongoing to try and determine the genetic contribution to mental illnesses, such as schizophrenia and bipolar disease. Families with a higher incidence of such illnesses have been key to such research. But with this complex disease, there is probably no single gene responsible. Ongoing research is determining genes and other factors that contribute to a higher incidence. For more specifics on progress being made with autism one site that may be useful is http://www.cureautismnow.org and visit the research page describing the genomics initiative Another site to visit for genetic information visit http://ghr.nlm.nih.gov Thanks! Q: Jonny Pistachio, Florida: Does the two parts of a DNA helix always go in a specific direction? (a start and a finish, spinning in a clockwise or counterclockwise pattern?) A: John Hodges, M.S.: Yes, DNA is a polar macromolecule. Each strand of the double helix is composed of chemical subunits which can be thought of as having a head and a tail, these are called 5' and 3' ends. By convention, when a research reads a DNA sequence the top strand runs in the 5' --> 3' direction while the bottom strand runs in the opposite orientation, 3' --> 5'. This configuration is called, 'antiparallel'. There are also a few basic kinds of DNA helices: A, B, and Z DNA. The most common, B-DNA, which is the form present in our chromosomes, is a right handed double helix 2nm in diameter. It also has 10 bp per turn of the helix with a twist of 36 degrees per base pair. Q: M Chaney, FL: Are identical twins DNA still identical when they are 90 years old, 40, 20, 10? A: Belen Hurle, Ph.D.: At the genetic level, they start off as identical but they can accumulate mutations in a different way: say one of them works in a nuclear plant and the other doesn't. As individuals, they are never identical from the very beginning -say one of them put more weight on during pregnancy - and they are exposed to different environments, friends, teachers, lifestyle, and so on. Q: Zeba Race, Newton, MA: Do you work in collaboration with scientists from other fields? A: Heidi Parker, Ph.D.: Yes, almost all of our work is done in collaboration with other scientists. By enlisting the talents of people with a variety of specialties you get a unique view of your subject and come up with a creative way of addressing it.
Q: Lita, High Point NC! GO RED RAIDERS!!!!!!!: What is the structural feature that allows DNA to self-replicate? A: John Hodges, M.S.: DNA doesn''t "self-replicate" but depends on proteins in the nucleus to do this. DNA is a double stranded linear molecule. The two strands in the DNA double helix are templates of each other. There are four basic molecules that compose the larger macromolecule - A, G, T, C - and these behave chemically in certain ways: ''A'' pairs with ''T'' and ''G'' pairs with ''C''. So, in a strand of DNA with the top sequence reading A - T - T - C - G - G, the bottom strand would read T - A - A - G - C - C. During DNA replication the two strands separate and the proteins that replcate DNA can read one strand to produce a partner pairing strand by using the base pair rule above. You can try this by writing on a sheet a paper a string of random letters composed of As, Gs, Ts, and Cs. Once you''ve done this, fill in the bottom strand using the base pair rule - A pairs with T, G pairs with C. Then separate and copy these two sequences on different parts of your sheet of paper and repeat this process. You should find that you can repeat this as many times as you want, always faithfully replicating the DNA helix. Q: Maria Makris, St. Paul's School for Girls: What academic path would advise a student who is interested in genetic counseling to take in college? A: Don Hadley, M.S., C.G.C.: Since the practice of genenetic counseling requires knowledge from multiple areas, I would encourage you to take a broad collection of courses that include both the basic sciences (biology, biochemistry, genetics, etc.) as well as social sciences (psychology, sociology, anthropology, etc.). A more detailed answer to your question can be found through the internet through the National Society of Genetic Counselors' website (www.nsgc.org). You should also know that genetic counselors typically have a Masters degree (graduate degree) from one of the approximately 30 genetic counseling programs in the United States. The NSGC website (http://www.nsgc.org/careers/index.asp) will direct you to those programs' websites. Each program will also give you an answer about pathways to genetic counseling. Good luck. Q: Erik, Chicago: Is depression hereditary? A: Holly Peay, M.S., C.G.C.: Depression is what we call a multifactorial disorder, meaning that both genetic and environmental factors play a role. Researchers are beginning to identify the genes and environmental factors involved in depression. It is extremely complicated, though. In some families we think that there are strong genetic factors, while in other families there are weak genetic factors and strong environmental factors. To make matters more complicated, there is not one "depression gene"- there are likely to be many genes that increase risk to depression by modifying how one interacts with one's environment. So the answer to your question is that yes, depression is partly hereditary, but the environment is important as well.
Q: Jenny, NY: Can your DNA predetermine whether you will have musical talent or not? A: Vivian Ota Wang, Ph.D.: Although many people believe that DNA can predetermine whether a person will have musical talent, musical talent is much more complicated than just someone's DNA. Besides someone's genetic makeup, his or her environment, motivation to practice, etc also contributes to someone's potential musical ability. Q: lazara geneva ny: What kinds of DNA are there? A: Nate Sutter, Ph.D.: Great question! Although the rules in biology are often defined by exceptions to them, DNA is one of the great constants. DNA is used by bacteria, worms, flies, trees, algae, mice, monkeys, and humans to store and transmit information. This is done with the familiar 'A', 'C', 'G', and 'T' bases we know about. What makes us different from trees and worms is the particular order of the bases along the chromosomes. So while every DNA molecule has similar chemical properties, the particular sequence in a tree will be different from a human. Q: Mrs. Talley's Nashville High Biology: Do co-joined twins have the exact same DNA? If not, how do they differ? A: Belen Hurle, Ph.D.: if they are co-joined because they are the result of one embryo that partially split during development, the answer is yes. If they are co-joined because two independent embryos got fused together during development, the answer is no. Q: Jackie from Baltimore, Maryland: Are there certain regions or cultures that do or do not support this type of research more than others? A: Vivian Ota Wang, Ph.D.: This is an interesting question that many people ask. In part, what each person understands what genetic research is (and Isn''t) will influence whether they support genetic and genomic research. Because of this, at some level, in all cultures and regions there are people who support and not support genetic research. This can seem confusing at times since you may hear different opinions from people of the same culture. The bottom line is there is probably no one answer for a particular cultural group. I would encourage you to ask your question to many types of people from different cultures to explore the various ways they see genetic research...you may be pleasantly surprised by their responses. Q: Trieneke, Canada: In order for DNA to be transcribed, RNA polymerase typically combines with a series of protein promoters, allowing it to latch on to a gene sequence. How are the promoters themselves transcribed? A: Nate Sutter, Ph.D.: RNA polymerase is itself a protein. All proteins are produced when DNA is transcribed into RNA, as you mention, and RNA is translated into protein. Some of these proteins, called transcription associated factors, help to "promote" the transcription process. The proteins working to transcribe a gene at any given time were previously translated. In other words, there is a pool of protein machines that at any given point are being lost yet also being replenished by freshly translated proteins. The cell can't ever stop working! Q: Y.M: Do genetics have anything to do with the type of people we fall in love with? A: Vivian Ota Wang, Ph.D.: Although many people may wish that DNA can help one easily find the "love of one's life," it's never really that easy since a person's choices are a complicated combination of personal preferences, opportunity, one's personality, environement, etc.and not solely based on genetics. Q: Dobrov - St. Ignatius College Prep: Since twin studies form the basis of research on behavioral genetics - would it be worthwhile looking at twins for differences in numbers of repeat sequences, epigenetic markers, etc. that may lead to underlying factors of behavioral 'disorders'and a better understanding of the so-called "alternative genome?" A: Holly Peay, M.S., C.G.C.: Yes, these sorts of twin studies could be useful to researchers. Unfortunately, this is difficult in practice. The first |
