January 13, 2010
Y Chromosome Still Evolving

Some have theorized that the Y chromosome is in decline, that the chromosome that makes men into men is losing out in the rush of evolution. But no. I'm sure many guys will be happy to know that the Y chromosome is evolving under heavy evolutionary pressure.

CAMBRIDGE, Mass. (January 13, 2010) – Contrary to a widely held scientific theory that the mammalian Y chromosome is slowly decaying or stagnating, new evidence suggests that in fact the Y is actually evolving quite rapidly through continuous, wholesale renovation.

By conducting the first comprehensive interspecies comparison of Y chromosomes, Whitehead Institute researchers have found considerable differences in the genetic sequences of the human and chimpanzee Ys—an indication that these chromosomes have evolved more quickly than the rest of their respective genomes over the 6 million years since they emerged from a common ancestor. The findings are published online this week in the journal Nature.

"The region of the Y that is evolving the fastest is the part that plays a role in sperm production," say Jennifer Hughes, first author on the Nature paper and a postdoctoral researcher in Whitehead Institute Director David Page's lab. "The rest of the Y is evolving more like the rest of the genome, only a little bit faster."

A lot of other versions of the Y chromosome fell by the wayside so that our versions could emerge victorious over all those loser Ys. This should not be surprising. One guy can knock up a lot of women. The competition between males to reproduce is much stiffer than the competition between females. More Y chromosomes than X chromosomes lose the race to reproduce in each generation.

The Y chromosome is undergoing renovation.

The results overturned the expectation that the chimp and human Y chromosomes would be highly similar. Instead, they differ remarkably in their structure and gene content. The chimp Y, for example, has lost one third to one half of the human Y chromosome genes--a significant change in a relatively short period of time. Page points out that this is not all about gene decay or loss. He likens the Y chromosome changes to a home undergoing continual renovation.

"People are living in the house, but there's always some room that's being demolished and reconstructed," says Page, who is also a Howard Hughes Medical Institute investigator. "And this is not the norm for the genome as a whole."

Human evolution has been happening quite rapidly. Once genetic testing for embryo selection becomes widespread human evolution will accelerate at a much faster rate than that seen in the recent 10,000 year explosion. The next decade will witness an explosion of human genetic revelations which (in addition to upending politically correct ideologies) will enable people to select embryos that contain much more optimal genetic variations. This will reduce the risk of having offspring not as good looking, healthy, or bright as their parents. Newer generations will be better looking, healthier, and smarter.

Share |      Randall Parker, 2010 January 13 10:26 PM  Trends, Human Evolution

Zach said at January 14, 2010 9:22 AM:

"The competition between males to reproduce is much stiffer"

Sorry, but I can't resist remarking that that is indeed an interesting choice of words.

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