The Evolution of Sex: Rethinking the Rotting Y Chromosome

12/08/2003 4:00 PM McGovern AuditoriumDavid C. Page, Associate Director of Science, Whitehead Institute; Professor of Biology, MITDescription: According to David Page, "the Y chromosome is the Rodney Dangerfield of the human genome." Regarded for 50 years as a genetic wasteland, the Y chromosome just doesn't get any respectEURuntil now. Page's lab has made some startling discoveries that reverse the prevailing view.

Recall from basic biology that pairs of chromosomes exchange genetic material through a process of crossing over. This leads to genetic variation in offspring, and can weed out dangerous mutations. Although there's limited gene swapping between the sex-determining X and Y chromosomes, the popular belief has been that a large portion of the Y could not recombine, and therefore will sooner or later self destruct. The long-term outlook for the Y chromosome was bleak.

But now there is hope and renewed respect for the Y. Page has found vast sequences of DNA on the Y that appear like palindromes (words like "mom" that read the same backwards and forwards). Page believes the two halves of the palindrome engage in a kind of crossing over. This can lead to repairing mutations, just as in ordinary chromosomes. Through this unique method, the Y chromosome not only endures but prevails.
About the Speaker(s): David C. Page studies the Y chromosome the chromosome that distinguishes males from females. In 1992, his laboratory mapped and cloned the entire Y chromosome. Today, he uses the map and other tools to trace the genetic causes of male infertility, the history of the Y chromosome and human populations, and the origins of common genetic diseases. He is also chair of the Whitehead Task Force on Genetics and Public Policy. Page received his MD degree with a concentration in genetics in 1984 from Harvard Medical School and the Harvard-MIT Health Sciences and Technology Program, and was immediately appointed a Whitehead Fellow. He joined the faculty of the Whitehead Institute and MIT in 1988. His honors include a MacArthur Foundation Prize Fellowship in 1986, a Searle Scholar's Award in 1989, and the Amory Prize for advances in reproductive biology from the American Academy of Arts and Sciences in 1997.Host(s): School of Science, Whitehead Institute for Biomedical ResearchTape #: T18064

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