There are maybe half a dozen genes that are attracting special attention by Lahn's research group. Here's an abstract of a recent paper from his group.
Science 9 September 2005:
Vol. 309. no. 5741, pp. 1720 - 1722
DOI: 10.1126/science.1116815
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Reports
Ongoing Adaptive Evolution of ASPM, a Brain Size Determinant in Homo sapiens
Nitzan Mekel-Bobrov,1,2 Sandra L. Gilbert,1 Patrick D. Evans,1,2 Eric J. Vallender,1,2 Jeffrey R. Anderson,1 Richard R. Hudson,3 Sarah A. Tishkoff,4 Bruce T. Lahn1*
The gene ASPM (abnormal spindle-like microcephaly associated) is a specific regulator of brain size, and its evolution in the lineage leading to Homo sapiens was driven by strong positive selection. Here, we show that one genetic variant of ASPM in humans arose merely about 5800 years ago and has since swept to high frequency under strong positive selection. These findings, especially the remarkably young age of the positively selected variant, suggest that the human brain is still undergoing rapid adaptive evolution.
Just a moment...
This particular variant is not present in all humans but is the most recent development found. So, although it appeared around 6000 years ago, it doesn't really help a creationist viewpoint. Another more recent paper has questioned the notion the gene is undergoing positive selection (Currat et al., 2006). A mutation of ASPM causes microencephaly.
Employing the above strategy, we identified a number of candidate genes that might have played a role in human brain evolution. Examples include ASPM, Microcephalin, CDK5RAP2, CENPJ, Sonic Hedgehog, APAF1, and CASP3. A remarkable theme unifying all these genes is their involvement in determining neuronal cell number and brain size during embryonic development. When any one of these genes is mutated in either human or mouse, the result is a dramatically reduced brain size. For a subset of these genes, reduction in brain size appears to be the only discernible defect in the organism, indicating a highly specific function of the genes in regulating brain size. These findings led us to postulate that genes controlling brain size during development might have played a particularly important role in transforming brain size during evolution.
Bruce T. Lahn, PhD | HHMI
These are the others that are under examination. Not to say these are the only genes involved in the evolution of the human brain, of course.
The Lahn group are doing some very interesting stuff.
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