African Mountain Gorillas May Inbreed to Survive Habitat Shrinkage

Scientists have created the first ever whole genome sequencing of the endangered mountain gorilla. The findings reveal these animals may actually be able to cope well with inbreeding.

"Mountain gorillas are among the most intensively studied primates in the wild, but this is the first in-depth, whole-genome analysis," said Chris Tyler-Smith, one of the researchers, in a news release. "Three years on from sequencing the gorilla reference genome, we can now compare the genomes of all gorilla populations, including the critically endangered mountain gorilla, and begin to understand their similarities and differences, and the genetic impact of inbreeding."

There is only a small number of mountain gorillas living in the Virunga volcanic mountain range on the borders of Rwanda: only about 253 in 1981. This was largely due to a result of habitat destruction and hunting. Since then, conservation efforts have tried to help save this species. Today, numbers are up to about 480.

That said, this is still a relatively small gene pool. The researchers decided to get a better look at the genetics of this animal by using blood samples collected over several years. This allowed the scientists to sequence the whole genomes of seven mountain gorillas for the first time ever.

The researchers found that the gorillas were two to three times less genetically diverse than gorillas from larger groups in western regions of central Africa. While there are concerns about this low genetic diversity, though, the inbreeding has been beneficial in some ways. Fewer loss-of-function variants can be found in the mountain gorilla populations.

"We worried that the dramatic decline in the 1980s would be catastrophic for mountain gorillas in the long term, but our genetic analyses suggest that gorillas have been coping with small population sizes for thousands of years," said Yali Xue, first author of the new study. "While comparable levels of inbreeding contributed to the extinction of our relatives the Neanderthals, mountain gorillas may be more resilient. There is no reason why they should not flourish for thousands of years to come."

The findings are published in the journal Science.

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