Single gene differentiates human brain from other
WillWare writes "Articles at New Scientist and EurekAlert discuss a finding that a single mutated gene may account for the larger size of human brains relative to those of other primates. The gene involved appears to influence or control the muscle mass used by the jaw in biting. In humans the bite muscle is weak, and consequently the skull is permitted to grow larger and permit the brain to do likewise. This might affect the feasibility of the Open-source Bonobo project."
March 31st, 2004 at 4:45 PM
May be overblown.
Will, while I agree that it could be a factor it seems like there are enough differences between primate and human brains (and the genetics — we have the human and much of the chimp genetic code now. Just where is the article that says that all of "these" changes in the genomic code are important and all of "those" changes in the genomic code aren't? We are talking many thousands of base pairs even though most of the billions are identical). It seems really doubtful that you could pin the differences down to a specific gene. Possible? perhaps. Probable? Seems to be a real stretch to me. I would tend to lean towards scientists overhyping a finding.
Robert
April 4th, 2004 at 3:15 PM
Size isn't Everything
That the one little gene could be responsible for a gross size difference I have no trouble swallowing, but (and heads up, Robert B) other differences such as protein transription rates (10 or 100 times faster in human neural tissue than in our closest primate relatives) might be instigated by additional differences in genome or activities promoted even by epigenetic factors.
April 5th, 2004 at 8:06 AM
Re:May be overblown.
We are talking many thousands of base pairs even though most of the billions are identical… It seems really doubtful that you could pin the differences down to a specific gene.
I was careless in my phrasing. I don't literally believe that just one gene differentiates human brains from those of other primates. Maybe this smaller jaw muscle was a necessary prerequisite to human intelligence, and maybe other genetic differentiations might have offered little or no advantage until the larger braincase became available.