On-line Ed Kit

Understanding Biological Function

Knowing the DNA sequence of a gene reveals the basic structure of the protein that gene encodes. Scientists can sometimes deduce the 3-dimensional shape and function of the protein as well. Often, they can classify the protein because of similarities to other proteins. For instance, when scientists discovered the gene for cystic fibrosis, the sequence immediately suggested that the CF protein is a gatekeeper embedded in the membrane that surrounds a cell. The sequence also implied that the protein specifically allows salt to pass through the membrane. This fit nicely with the idea that a problem with the transport of salt and water might cause CF and explains why mucus tends to dry up in the lungs of people with the disease.

Even roundworms and fruit flies share many similiar genes with us

Experimental animals play an important role in helping scientists under- stand the biological function of genes. Human genes have relatives in the genomes of other animals. Even species as seemingly different from us as yeast, roundworms, or fruit flies share many similar genes. In fact, comparing DNA from different species and finding stretches where the sequence is conserved can highlight particularly important features. Often, insights about human diseases come when a newly discovered human disease gene has a close relative in another species such as the mouse or even the fruit fly-species where the role of that gene can be studied and placed in context. For example, the role of some human genes in cancer is understood better than otherwise possible because scientists have studied related genes in flies, finding that many of them guide embryonic development. In both casespreventing cancer and developing normally-cell communication is key.









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