Humans only 94% similar to chimps, not 98.5%
|December 28, 2006||Posted by scordova under Biology, Science|
A lot more genes may separate humans from their chimp relatives than earlier studies let on. Researchers studying changes in the number of copies of genes in the two species found that their mix of genes is only 94 percent identical. The 6 percent difference is considerably larger than the commonly cited figure of 1.5 percent.
This makes ReMine’s argument for revisiting Haldane’s Dilemma more compelling because now we’re having to account for how so many nucleotides are fixed in the human and chimp populations such that we have about a 180,000,000 base pair difference from chimps.
Darwinian evolution simply does not have the population resources to fix that many base pairs of difference (not enough individuals, not enough mutations, not enough time). We could of course try to make appeals to neutral theory, but a neutral scenario would also be hard pressed to account for the fixation of that many nucleotides as well…
How does evolution fix into the population things like duplicated genes that have little or no selective advantage via Darwinian evolution? Perhaps not through Darwinian evolution, but through genetic drift in small populations. But how long would that take, and is it consistent with sequence divergences between the duplicated genes and their supposed timelines of origin?
One might appeal to some scenario of rapid neutral evolution followed by an extreme recent bottleneck (so as to account for the low between-same-species sequence diveregence). Furthermore the bottleneck would have to have been simultaneously in effect for both chimps and humans. Heck, the bottleneck would have to be for almost every species out there, and timed appropriately! But would all this be yet another implausible “just so” story?
Haldane’s dilemma has possibly been multiplied by these new discoveries. The population genetics of this should be revisited in light of the new numbers, but I suspect the end conclusion will be difficult for either the Darwinian selectionists or the neutralists or anyone advocating mindless evolution.
HT: David Coppedge at CreationSafaris.com