Humans and chimps share genetic strategy in battle against pathogens

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A genome-wide analysis searching for evidence of long-lived balancing selection—where the evolutionary process acts not to select the single best adaptation but to maintain genetic variation in a population—has uncovered at least six regions of the genome where humans and chimpanzees share the same combination of genetic variants.

The finding, to be published Feb. 14 in the journal Science, suggests that in these regions, dates back to a with chimpanzees millions of years ago, before the species split. It also highlights the importance of the dynamic co-evolution of human hosts and their pathogens in maintaining genetic variation.

Balancing selection allows evolution to keep all hereditary options open. The classic human example is the persistence of two versions of the hemoglobin gene: a normal version and hemoglobin S., a mutation that distorts the shape and function of . Those who inherit two normal hemoglobin genes are at high risk for malaria, a that infects more than 200 million people each year. Those who inherit one normal gene and one S. gene are partially protected from malaria—a potentially life-saving benefit. Those with two copies of the gene suffer from sickle-cell anemia, a serious and lifelong .

“When we looked for pointing to other, more ancient, examples of balancing selection, we found strong evidence for at least six such regions and weaker evidence for another 119—many more than we expected,” said study author Molly Przeworski, PhD, professor of and of ecology and evolution at the University of Chicago.

“We don’t yet know what their functions are,” she said. None of the six regions codes for a protein. There are clues that they are involved in host-pathogen interactions, “but which pathogens, what immune processes,” she said, “we don’t know.”

Written By: PhysOrg
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  1. No one seems to be commenting here?

    For those who perhaps don’t appreciate the significance of this kind of thing you might want to read ‘The Red Queen’ – by Matt Ridley, a now long-since discredited banker. But very interesting anyway. (He may have been discredited as a banker and plutocrat but he’s apparently a reasonably good as a pop science writer. He may have participated but he doesn’t claim any particular expertise in economics, political corruption, or superannuation fraud.)

    The gist of it is that Ridley has interviewed a wide variety of research experts and his book discusses the idea of sexual reproduction as an evolutionary innovative response to ongoing parasite evolution. Which has implications for human nature (and presumably chimp and common ancestor nature).

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