Friday, August 31, 2012

More on Modern Human Origins

Scientific American is running a story on more news from the Max Planck Institute. Now, the entire genome of the hominins represented by the material from Denisova Cave has been sequenced. Here is what we find:
Unfortunately, the Denisovan genome doesn't provide many more clues about what this hominin looked like than a pinky bone does. The researchers will only conclude that Denisovans likely had dark skin. They also note that there are alleles "consistent" with those known to call for brown hair and brown eyes. Other than that, they cannot say.

Yet the new genetic analysis does support the hypothesis that Neandertals and Denisovans were more closely related to one another than either was to modern humans. The analysis suggests that the modern human line diverged from what would become the Denisovan line as long as 700,000 years ago—but possibly as recently as 170,000 years ago
Given the amount of genetic similarity in the three groups, it makes more sense that the number is closer to 170,000, especially since there is evidence of hybridization between the three groups. What also seems to be true is the Denisova group shows some level of founder effect in the sense that the genetic variability is more restricted than that found in modern humans. Who the population split off from is anybody's guess right now.

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