Using data from the gorilla genome of Susie, an 11-year-old Western lowland gorilla at Ohio's Columbus Zoo, scientists have shed light on the genetic similarities and differences between people and gorillas - our closest living relatives.
The new gorilla genome revealed that gorillas and humans show more genetic relation than previously believed, with a divergence of just 1.6 percent. Aside from these endangered apes, only chimpanzees and bonobos show such a close relation to our species.
Despite this seemingly small difference, there are numerous separations between our genetic code and theirs in the following areas: immune and reproductive systems, skin and fingernails and the regulation of the insulin hormone, which regulates blood sugar levels.
"The differences between species may aid researchers in identifying regions of the human genome that are associated with higher cognition, complex language, behavior and neurological diseases," said Christopher Hill, lead author of the study. "Having complete and accurate reference genomes to compare allows researchers to uncover these differences."
The team's genomic sequencing stems from a blood sample gathered from Susie, which took place while she lived at Chicago's Lincoln Park Zoo. Eventually, the researchers plan on creating a comprehensive catalog of the genetic differences between humans and the great apes, the taxonomic family that encompasses gorillas, orangutans, chimpanzees and bonobos.
"My motivation in studying human and great ape genomes is to try to learn what makes us tick as a species," said Evan Eichler, senior author on the study. "I'd like to see a re-doing of all the great ape genomes, including chimpanzee and orangutan, to get a comprehensive view of the genetic variants that distinguish humans from the great apes. I believe there is far more genetic variation than we had previously thought. The first step is finding it."
In addition to differences between humans and apes, the new gorilla genome assembly sheds light on the evolutionary history of lowland gorillas, revealing that the bottleneck that affected past gorilla populations was much more intense than previous research suggested.
"I think the take home message is that the new genome technology and assembly bring us back to the place we should have been 10 years ago," Eichler said. "Sequencing technology and computational biology," Eichler and his team wrote in their paper, "have now advanced to the stage where individual laboratories can generate high quality genomes of mammals. This capability has the promise to revolutionize our understanding of genome evolution and species biology."
The findings were published in the April 1 issue of Science.
