Gene regulation, not just genes, is what sets hu...( DURHAM N.C. -- The striking differen...)

DURHAM, N.C. -- The striking differences between humans and chimps arent so much in the genes we have, which are 99 percent the same, but in the way those genes are used, according to new research from a Duke University team.

Its rather like the same set of notes being played in very different ways.

In two major traits that set humans apart from chimps and other primates those involving brains and diet gene regulation, the complex cross-talk that governs when genes are turned on and off, appears to be significantly different.

Positive selection, the process by which genetic changes that aid survival and reproduction spread throughout a species, has targeted the regulation of many genes known to be involved in the brain and nervous system and in nutrition, said Ralph Haygood, a post-doctoral fellow in the laboratory of Duke biology professor Gregory Wray.

Haygood is lead author in a report on the research to be published online on Sunday, Aug. 12, in the research journal Nature Genetics.

His group looked at the regulatory sequences immediately adjacent to 6,280 genes on the DNA of chimps, humans and the rhesus macaque, a more distant primate relative that has 88 percent the same genes as humans. These regulatory stretches of DNA are where proteins bind to the genome to initiate a genes function. And it is here that evolution has apparently fine-tuned the performance of genes, Wray said, resulting in the dramatic differences in the human brain.

Though many studies have looked for significant differences in the coding regions of genes relating to neural system development and failed to find any, the Duke team believes this is the first study to take a genome-wide look at the evolution of regulatory sequences in different organisms.

Other studies have found significant differences between these species in the coding regions that govern the immune system, the sense of smell and the manufacture o
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