In a new study, Duke University researchers have found that hybrid baboons got about a third of their genes from another closely related species. The experts found evidence that some of these borrowed genes came at a cost to the crossbred animals.
The genetic study focused on wild baboons in southern Kenya, near Amboseli National Park, where yellow baboons often meet and mix with Anubis baboons from the northwest. These individuals have been monitored since 1971 as part of the Amboseli Baboon Research Project. Project scientists have documented when the animals mated with outsiders and observed the offspring throughout their lives.
Based on five decades of observations, there have been no clear signs that hybrids perform worse than their counterparts. In fact, baboons with more anubis DNA in their genomes were found to mature faster, form stronger social bonds and have more mating success.
The Duke study, however, indicates that there are possible consequences of the mix that are not so obvious. Professor Jenny Tung, who led the study with her PhD students Tauras Vilgalys and Arielle Fogel, said the research sheds light on how species diversity is maintained on Earth even when genetic lines between species are blurred.
According to Fogel, interspecies mating is surprisingly common in animals: 20 to 30 percent of apes, monkeys and other primate species interbreed and mix their genes with others.
The researchers set out to investigate the potential costs and benefits of genetic mixing in primates, including humans. They analyzed the genomes of 440 Amboseli baboons over nine generations.
The study revealed that all Amboseli baboons are a mix, with anubis DNA making up an average of 37 percent of their genomes. Some of the crossings were recent, within the last seven generations. For about half of the baboons, however, admixture occurred hundreds or thousands of generations ago.
During this time, the data show that certain fragments of Anubis DNA came at a cost to the hybrids who inherited them, affecting their survival and reproduction in such a way that these genes are less likely to appear in genomes today of his descendants, he explained. Vilgalys.
The researchers said the Amboseli baboons offer clues about the costs of hybridization. Vilgalys noted that genomic data allows researchers to look back many more generations and study historical processes that cannot be seen directly in the field.
“But you have to look at the animals themselves to understand what the genetic changes really mean,” Professor Tung said. “You need both fieldwork and genetics to get the whole story.”
“We’re not saying that’s what Neanderthal and Denisovan genes did in humans. But the baboon case makes it clear that genomic evidence for the costs of hybridization can be consistent with animals that not only survive, but often thrive.”
The study is published in the journal Science.
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By Chrissy Sexton, writer for Earth.com