HUMANS and gorillas last shared a common ancestor 10 million years ago, according to an analysis of the first full sequence of the gorilla genome. The gorilla is the last of the living great apes - humans, chimpanzees, gorillas and orangutans - to have its complete genetic code catalogued.

Scientists, led by researchers from the Wellcome Trust Sanger Institute near Cambridge, England, and Baylor College of Medicine in Houston, Texas, also found that 15 per cent of the gorilla's genetic code is closer between humans and gorillas than it is between humans and chimpanzees, our closest animal relative. The genomes of all three species are, in any case, highly similar: humans and chimpanzees share more than 98 per cent of their genes, while humans and gorillas share more than 96 per cent.

Despite the evolutionary split with gorillas around 10 million years ago, we still share a remarkable number of genes with the great ape. Credit:AFP

The genetic sequence was taken from a female western lowland gorilla named Kamilah and published in the science journal Nature.

''Gorillas are an interesting animal in their right but the main reason they are of particular interest is because of their evolutionary closeness to us,'' said Aylwyn Scally, an author of the research from the institute. ''They're our second-closest evolutionary cousins after chimpanzees and knowing the content of the gorilla genome enables us to say quite a lot about an important period in human evolution when we were diverging from chimpanzees.''

Studying the gorilla genome suggests that the divergence of gorillas from the common ancestor of humans and chimpanzees happened around 10 million years ago. Humans and chimpanzees last shared a common ancestor around 6 million years ago. Eastern and western gorillas split some time in the last million years.

One curious find was the evolution of genes associated with hearing, which seem very similar between humans and gorillas. ''Scientists had suggested that the rapid evolution of human hearing genes was linked to the evolution of language,'' said Chris Tyler-Smith, senior author from the Wellcome Trust Sanger Institute. ''Our results cast doubt on this, as hearing genes have evolved in gorillas at a similar rate to those in humans.''

Guardian News & Media