The mountain gorilla, which lives in Virunga volcanic mountain on the borders of Rwanda, Uganda and the Democratic Republic of Congo is facing the very real possibility of extinction. The numbers have rebounded in recent years, from 253 living animals in 1981 to an estimated 880 today.
The decline in mountain gorilla populations, however, is not a new thing. The population appears to have been shrinking in numbers for centuries.
Researchers recently sequenced the genomes of different gorillas to assess the impact of long-term population decline on the health and diversity of the species.
Researchers originally thought that the decline in genetic diversity would make the animals more susceptible to disease and environmental change. However, according to the results, the decline in genetic diversity due to inbreeding has actually been beneficial to the mountain gorillas.
“These data show us the genetic derivation and the process by which genomes create mechanisms to eradicate deleterious recessive mutations,” says the research leader, Chris Tyler-Smith, Institute Sanger researcher in a statement.
Analysis of the mountain gorilla genes showed that there were fewer harmful variations in the population than in other western gorilla populations. Many of the missing variations are thought to lead to significant health problems.
“Three years after the first sequenced of an individual reference genome, followed by the one of Copito de Nieve, and then by more than 30 gorillas genomes, now we can compare the genomes of all four Gorilla subspecies, including the mountain gorilla, and we can also start to understand their similarities and differences, and the genetic impact inbreeding”, said doctor Tomàs Marquès-Bonet, researcher at Institute of Evolutionary Biology and at the National Genome Analysis Centre.
Thanks to conservation efforts 480 mountain gorillas now live in the Virunga volcanic mountain region and an additional 400 animals live about 18 miles north.
“This new understanding about the genetic diversity and the demographic history of gorillas populations provided to us a valuable information about how apes and therefore humans are genetically adapted to live in small populations,” says Aylwyn Scally, from Cambridge University.
The results of the research come as a great relief to researchers who were concerned that the lack of genetic diversity would make the extinction of the mountain gorilla a question of when and not if.
“We are worried that the drastic decline in the 80’s were catastrophic to mountain gorillas in long term, but our genetic analysis suggest that gorillas have faced to small populations size during thousand of years, more than expected. Despite similar levels of inbreeding contributed to the extinction of Neanderthal, mountain gorillas can be stronger. There is no reason for them not to have survived in those conditions during thousand of years,” says Javier Prado-Martínez, from Institute of Evolutionary Biology.
Researchers hope that a better understanding of the genetics and genetic diversity of mountain gorillas, as well as related species, will help to improve conservation efforts.
The World Wildlife Federation (WWF) lists habitat loss, disease, illegal charcoal harvesting and poaching as the greatest current threats to the mountain gorilla population.
The detailed findings of the genetic research can be found in the journal Science.
