Ancient hookups gave chimps a smidge of bonobo DNA
Genetic analysis traces previously unknown primate hybridization
Like lipstick on a collar, new DNA evidence is pointing to ancient affairs between bonobos and chimpanzees.
Chimps carry a small percentage of bonobo DNA, researchers report in the Oct. 28 Science. The conclusion comes from analysis of the genetic instruction books, or genomes, of 63 wild-born chimps, two captive chimps named Clint and Donald, and 10 wild-born bonobos. The apes came from 10 African countries.
Although chimps (Pan troglodytes) and bonobos (Pan paniscus) became separate species 1.6 million to 2 million years ago, they are still closely related enough to interbreed occasionally. Finding bonobo genetic variants in chimp DNA suggests at least two past periods of interspecies intimate relations. Between about 550,000 and 200,000 years ago, bonobos mated with the ancestors of eastern and central chimp subspecies. Subsequent mating between chimp subspecies probably carried some bonobo DNA into the Nigeria-Cameroon chimpanzee subspecies. Central chimps and bonobos interbred again about 100,000 to 200,000 years ago, giving modern central chimps more bonobo DNA than their sister subspecies.