Monday, September 26, 2005

Men Aren't Going Extinct

Much to our relief, the rumors that the Y-chromosome is gradually falling apart are greatly exaggerated. It still only has 27 genes compared to 1,000 for the X, but at least things aren't getting worse. It had been theorized that over a few million years even those 27 would be lost, but Forbes tells us, "No worries:"
"But now researchers at the MIT-affiliated Whitehead Institute have compared the human Y chromosome to the chimpanzee counterpart, searching for genes that men may have lost or degraded since humankind diverged from chimps six million years ago. To their relief, they found not a single gene has been lost in that long period, indicating that the Y isn't falling after all.

By contrast, the researchers found that the chimpanzee male chromosome has lost five genes over the last six million years, which may be due to chimps' promiscuous sexual habits, the researchers theorized. Men have one X and one Y chromosome, while women have two X chromosomes.

'Somehow this idea...that the Y chromosome is headed for extinction...has achieved tremendous market penetration,' says Whitehead geneticist David Page, the senior author of the study. 'But despite all the doomsday scenarios, it actually looks like the Y is sailing along quite nicely. It has established a new lifestyle with fewer genes. Our species has a long to-do list, but I think we can cross this problem off the list. You can sleep a little better now.'"
Whew! Now, if I could just stop worrying about the Entropy Death of the Universe and the Big Crunch.

The DNA of humans and chimps are 98.8% identical, making them our closest non-human relatives. Yet there are still important differences, at least for most of us.
"Still, after all this work, researchers are only at the very earliest stages of figuring out why we are so much smarter than monkeys.

'The original idea was by comparing [chimps' genes]with the human genome we would discover why we write poetry or become reporters. Sadly today we can say almost nothing about that topic that we couldn't say before the chimp genome was done,' says Whitehead Institute's Page. 'We genomicists can pile up the DNA letters very quickly but are very primitive readers of the text. It is an overstatement to say we can read it at the first grade level.'"
We suggest starting with the comparatively easy problem, comparing the chimps to reporters, lawyers, and politicians.

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