Apr.21 : Genetic researchers from the University of Chicago, Harvard, the Broad Institute and Arizona State are claiming that there are three distinct types of chimpanzee.

In a study that appears in this month’s issue of the journal PLOS Genetics, the primatologists have claimed that central and eastern chimps are more closely related to each other than they are to the western “sub-species.”

“Finding such a marked difference between the three groups has important implications for conservation,” said Molly Przeworski, an assistant professor of human genetics at the University of Chicago and a senior author of the study.

“It means we have to protect three separate habitats, all threatened, instead of just one,” she added.

To unravel the evolutionary history to chimpanzees, the research team collected DNA from 78 common chimpanzees and six bonobos, a separate species of chimpanzee, and examined 310 DNA markers from each.

They found four “discontinuous populations,” three of common chimps plus the bonobos.

Hybrids, those with at least five percent of their DNA from more than one common chimpanzee population were rare, with most of the hybrid chimps born in captivity.

The original boundaries between groups may have been the emergence and growth of rivers, such as the Congo River, which is thought to be about 1.5-million-years-old.

The extent of accumulated genetic difference enabled the researchers to speculate about when the different populations separated.

They estimate that bonobos, which live south of the Congo River, split off from the ancestors of modern chimpanzees about 800,000 years ago.

Western chimps appear to have separated from central and eastern chimpanzees about 500,000 years ago and central and eastern chimps divided about 250,000 years ago.

“Even though the chimp genome has been sequenced, it’s amazing how little we know about their evolution and the level of variation within chimpanzees,” said Przeworski.

The chimpanzee genome differs from the bonobo genome by about 0.3 percent, which is one-fourth the distance between humans and chimps. Yet chimps and bonobos have radically different social systems, cultures, diets and mating systems.(ANI)