Mountain gorilla's genome reveals extensive inbreeding

Mountain gorillas are extensively inbred but this phenomenon represents an adaptation rather than a risk for the survival of the critically endangered apes, according to an international research that sequenced the animals' genome for the first time.

"Mountain gorillas are a critically endangered subspecies, only few hundred survive in the wild in two locations in tropical east Africa," Yali Xue, first author from Britain's Wellcome Trust Sanger Institute, told Xinhua.

"Very detailed field studies have been carried out on them by primatologists for decades, but very little is known about their genetics," Xue said.

There are four kinds of gorillas: mountain, eastern lowland, western lowland and cross river, but mountain gorillas are the only great ape species that have not had their whole genome sequenced, she said.

For their study, Xue and colleagues sequenced seven mountain gorillas from Africa's Virunga region and compared the genomes of these animals with those of three other Gorilla subspecies.

"We found evidence of extensive inbreeding," Xue said. " Mountain gorillas are genetically different from other gorillas, have experienced prolonged population decline over the past million years, resulting in very low genetic diversity."

Typically, inbreeding increases the threat from disease and environmental change, but the new study showed that for mountain gorillas, it also results in the elimination of many harmful genetic mutations from the population.

By analyzing the variations in each genome, the researchers discovered that mountain gorillas have survived in small numbers for thousands of years, far longer than previously thought.

"So, with suitable human help for their conservation, they should be able to survive for thousands of years to come," said an optimistic Xue.

The study, involving researchers from Britain and five other countries, was published in the Friday issue of the U.S. journal Science. Endite