WHEN KING Louie the orang-utan sang "I wanna be like you" to a human in the film Jungle Book, little did he know he had already achieved his goal. Thanks to the latest genetic analysis, we now also know how closely related we are to gorillas.
Researchers at the Wellcome Trust Sanger Institute this morning publish the complete gorilla genome, the fourth great ape genome to be delivered after those of humans, chimpanzees and orang-utans. It shows gorillas stand with humans and chimps in having rapidly evolving DNA, leaving poor King Louie behind with quite slowly evolving genes.
The delivery of the gorilla genome, taken from Kamilah, a female western lowland gorilla, now opens the way to highly detailed comparisons between the four living great ape species. Preliminary work has already shown that while the chimpanzee remains our closest living relative, a large block of our own genome more closely resembles that of the gorilla.
Previous studies have shown that humans and chimps share about 97 or 98 per cent of their DNA. But adding the gorilla genome to the mix, the Sanger team reports that 15 per cent of our genome is closer to the gorilla than the chimp. They also found a matching share of the chimpanzee genome is closer to the gorilla than to humans.
Perhaps more interesting – and the thing that separates these three species from that of King Louie – is the speed of gene evolution. About 500 genes related to sensory perception, hearing and brain development showed accelerated evolution in these three but in particular in humans and gorillas, the researchers report.
“We found that gorillas share many parallel genetic changes with humans, including the evolution of our hearing,” said senior author Dr Chris Tyler-Smith. This finding damages the theory that the fast evolution of human hearing genes is linked to the evolution of language. Gorillas experienced a similar fast evolution of hearing, but did not develop language like our own.
The genome analysis shows the human/chimp lineage parted from that of the gorilla about 10 million years ago, and that humans and chimps branched off in separate directions six million years ago.
The authors also note that human activity has pushed gorillas to the brink, leaving just a few isolated and endangered populations mostly in Central Africa’s equatorial forests. Action is needed lest this great ape disappears like another one has done – our cousin the Neanderthal.
