A probe is a single-stranded sequence of DNA or RNA used to search for its complementary sequence in a sample genome. The probe is placed into contact with the sample under conditions that allow the probe sequence to hybridize with its complementary sequence. The probe is labeled with a radioactive or chemical tag that allows its binding to be visualized. In a similar way, labeled antibodies are used to probe a sample for the presence of a specific protein.
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In doing genetics research, we often use something that we call probes. Probes are stretches of DNA or RNA that we've attached a label to. The label allows us to see where the DNA binds either in a cell, or in a chromosome, or even in pure isolated DNA. We label probes with different molecules to follow them. We can use radioactive material or fluorescent material to chemically attach it to a probe. And then we can use that probe to look for where certain mRNAs are expressed in a cell or in a tissue. We can also use probes to screen the genome to find out if there are extra copies, which often happens in cancers, or missing copies of certain parts of the genome, which happens in hereditary syndromes and in cancers.
Name: Lawrence C. Brody, Ph.D.
Occupation: Chief & Senior Investigator, Genome Technology Branch; Head, Molecular Pathogenesis Section
Biography: Dr. Brody investigates the genetics of breast cancer and neural tube defects. As chief of the NHGRI Genome Technology Branch's Molecular Pathogenesis section, he is interested in studying genetic mutations that lead to perturbations in normal metabolic pathways and cause disorders such as cancer and birth defects. His laboratory investigates mutations in two breast cancer-linked genes, breast cancer gene 1 (BRCA1) and breast cancer gene 2 (BRCA2). Dr. Brody's laboratory was among the first to report that women carrying BRCA1 or BRCA2 mutations have a higher risk of developing both breast and ovarian cancer than women without such mutations.