Friday, February 18, 2005

149: Comparing recombination in humans and chimps

Researchers interested in recombination compared the areas with frequent crossovers in humans and chimps, expecting that similar genetic codes would produce similar crossover hotspots.

Surprising difference between human and chimp genomes | Science Blog:

They identified 18 hotspots in humans and three hotspots in chimps. To their surprise, none of the hotspots occurred in the same locations in human and chimp.

"The surprising conclusion seems to be that there is probably something other than the DNA sequence, or perhaps in addition to it, that is determining where these hotspots are located," said Altshuler. "Epigenetic factors--biological codes that are layered on top of the DNA--may turn out to be more different in closely related species than the DNA sequence itself."
Why isn't this at The Non-Evolution Project? Because an evolutionary hypothesis generated a testable hypothesis. There are still naturalistic explanations; the story of the genome is just more complicated than it seems at first glance.

Remember, science is a method, not an encyclopedia. A hypothesis that fails is usually more interesting that a successful prediction. It means something interesting happened. It doesn't mean science failed, it means that one hypothesis failed. In this case, the hypothesis was that crossing over was dictated by the genetic sequence at the crossover site. That failed, and it helps explain why humans and chimps aren't identical. Evolution led us to interesting questions, and opened up a new frontier.