Genetic opposites attract when chimpanzees choose a mate

Chimps can tell genetically similar mates from more distant ones

 

Date: January 11, 2017

Source: Duke University

Flirt, a young female chimpanzee, left her brothers and other relatives behind when she reached puberty to reproduce in a new group. A study finds that chimps can tell genetically similar mates from more distant ones, even among unfamiliar partners.

When it comes to hookups in the animal world, casual sex is common among chimpanzees. In our closest animal relatives both males and females mate with multiple partners. But when taking the plunge into parenthood, they're more selective than it seems.

A study appearing online Jan. 11 in the journal Royal Society Open Science reveals that chimps are more likely to reproduce with mates whose genetic makeup most differs from their own.

Many animals avoid breeding with parents, siblings and other close relatives, said first author Kara Walker, a postdoctoral associate in evolutionary anthropology at Duke University. But chimpanzees are unusual in that even among nonrelatives and virtual strangers they can tell genetically similar mates from more distant ones.

The researchers aren't sure yet exactly how they discriminate, but it might be a best guess based on appearance, smell or sound, said senior author Anne Pusey, professor of evolutionary anthropology at Duke.

Researchers took DNA samples from the feces of roughly 150 adult chimpanzees in Gombe National Park, Tanzania, and analyzed eight to 11 variable sites across the genome. From these, they were able to estimate the genetic similarity between every possible male-female pair.

In chimpanzees, as in other animals, only some sexual encounters lead to offspring. When the researchers compared pairs that produced infants with those that didn't, they found that females conceived with sires that were less similar to them than the average male.

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