While it took over 10 years to fully sequence the human genome, modern technology means it is now much easier to decode the DNA of many other organisms. The information contained within each cell can provide a fascinating glimpse of what makes a species a species. Now researchers have managed to generate the most accurate reading of the gorilla genome, filling in hundreds of thousands of gaps. With this new information, the researchers hope they can meaningfully compare the gorilla genome with that of humans and other apes.
The gorilla genome was actually first sequenced back in 2012 by an international group of researchers, and was the last genus of great apes to get its full genome decoded. “The gorilla genome is important because it sheds light on the time when our ancestors diverged from our closest evolutionary cousins,” explained Aylwyn Scally, first author of the original study to sequence gorilla DNA, in a statement. “It also lets us explore the similarities and differences between our genes and those of the gorilla, the largest living primate.”
Due to the methods used to construct that first gorilla genome, there were over 400,000 sequence gaps, as well as some inaccurate genetic structuring. This meant that when comparing the gorilla genome with that of humans, many regions of the human genome could not be readily aligned with those of our largest living primate. This greatly limited the ability of researchers to make any comparisons. But by using more modern techniques, the new study published in Science is able to fill in an impressive 94 percent of these gaps, producing the most accurate reading yet of the gorilla genome.
Susie the female western lowland gorilla at Lincoln Park Zoo, whose DNA was sequenced for the project. Courtesy of Lincoln Park Zoo
The team took a DNA sample from a western lowland gorilla (Gorilla gorilla gorilla) named Susie, who lives in Lincoln Park Zoo in Chicago. Using what is known as long-read sequencing technology, as well as a bunch of algorithms, they were able to decode much longer stretches of Susie’s genome, making the resulting sequence far more accurate. They then compared it with the human genome to find there were an astonishing 117,512 points at which there was either additional or removed information.
They also found that while overall we are indeed more closely related to chimpanzees, there are regions of our DNA – some 15 percent of it in fact – that are more similar to gorillas. This, claim the researchers, is evidence of the rapid divergence of chimp, gorilla, and human lineages when they split millions of years ago.
The researchers hope that by filling in the holes, they can get a more meaningful understanding of the gorilla's DNA and also of what makes us human.