Genetics and Health

Humans 99% same genetically as primates - why are we so different?

by Elaine on August 15th, 2007

Following on from my blog on genetics and evolution, Dukes University, USA  has just published a fascinating piece of research on what genetic factors set us apart from primates.

In genetic terms man is 99% the same as primates so why have we evolved over the last million years?  It is all about gene regulation.  Think of the keys on a piano, they can be played in millions of combinations, each combination producing a different piece of music.  This is the same for our genes.  In man, gene regulation is making a different piece of ‘music’ to primates.  This evolution has enabled us to eat differently, develop a complex language, invent amazing technology etc etc.

The Dukes research led by Ralph Haygood, a post doc fellow in Professor Gregory Wray’s team, have published an article in Nature Genetics.  It appears to be the first study to take a genome-wide look at the evolution of regulatory sequences in different organisms.  It focuses on two traits which set humans apart from primates - our diet and our brain function. Gene regulation, the complex cross-talk that governs when genes are turned on and off, appears to be significantly different.

Prof Wray’s 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 gene’s function. And it is here that evolution has apparently fine-tuned the performance of genes, resulting in the dramatic differences in the human brain.

While the biochemistry that cells use to turn food into energy is essentially the same across most animal species, the fine-tuning of how an organism deals with the different sorts of sugars and complex carbohydrates in its diet lies in the regulatory sequences, Wray said.

Chimps are fruit-eaters, for the most part, and would not last long away from their fruit-rich forest. The sugars in their diet are relatively simple to break down and convert to cellular fuel. Humans, on the other hand, eat a wider array of foods, including many the chimps would simply not be able to digest like starchy root crops. The researchers found dramatic differences in the regulatory regions of their genes for breaking down more complex carbohydrates. It may be that parts of the human metabolism are cranked up to digest carbs down to simpler sugars.

“Regulatory changes have adapted to changing circumstances without changing the essential chemistry of metabolism,” Wray said. “This may set the stage for a more focused analysis of the human diet.”

Much is being written and hypothesized about how dietary changes have contributed to the current human pandemics of obesity and diabetes, and perhaps there will be some insights from understanding how these regulatory sequences have evolved, he said.”

For further information on Prof Wray’s team’s research visit:

http://news.duke.edu/2007/08/wrayregulation_print.ht

Penny

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POSTED IN: Genealogy and DNA, General Genetics and Health, Genetic Engineering, Genetic Future, Genetic Ingenuity