Sequences in the human genome that have undergone positive selection are found in abundance in regions that regulate the expression of genes involved in neural or nutritional processes, suggests a paper online in Nature Genetics. The study provides some of the first large-scale evidence that the evolution of some human-specific traits can be traced to changes in gene regulatory (promoter) regions.
Cognitive, behavioural and dietary differences are among the most obvious differences between humans and the great apes. Although one might expect that genes involved in these processes would show evidence of positive natural selection in humans since the most recent common ancestor of humans and chimpanzees, there is little evidence to support this.
Ralph Haygood and colleagues compared probable promoter regions for more than 6,000 genes in the human, chimpanzee and macaque genomes. They generated statistics to identify those promoters that likely had undergone positive selection in the human genome. At least 250 such promoters were found. Although they represent several functional categories, prominent among them are promoters linked to genes involved in neural development and function, including axon guidance, synapse formation and neurotransmission in the brain. Nutrition-related genes include a large number involved in glucose metabolism.
Ralph Haygood (Duke University, Durham, NC, USA)
Abstract available online.
(C) Nature Genetics press release.
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