Gene Regulation Is A Vital Part of Human Evolution

In NOT A CHIMP I chronicle the extraordinarily prophetical work of Allan Wilson and Mary-Claire King, a quarter century ago, which argued that mutational changes to the DNA sequence of genes - single nucleotide polymorphisms - alone could not possibly explain the myriad differences they recorded between humans and chimps. Something else had to be going on. They suggested that differences in gene regulation - the activity and timing of activity - of identical or highly similar genes would be found to be important. In those days limited genome technology prevented them from fully exploring this idea but recent work has dramatically supported their theory and shown a host of gene regulation differences between humans and chimps, especially in the brain. Now, a group of scientists which includes Carlos Bustamente and Andrew Clark, from Cornell University, has examined the phenomenon of cis-regulation - changes in DNA in non-coding intronic areas flanking more than 15,000 genes - and found patterns they interpret as a strong effect of both positive and negative selection during hominid history - and an especially strong effect of positive selection upon these regulatory sequences in genes operating in the foetal brain. As they conclude in their summary: "Our results suggest that both positive and negative selection have acted on candidate cis-regulatory regions and that the evolution of non-coding DNA has played an important role throughout hominid evolution."