Geneticists have completed a complete deciphering of the gorilla genome and have found that approximately 15% of gorilla genes are closer to their human counterparts than to those found in chimpanzee DNA, according to an article published in the journal Nature.
Comparative genealogy
Gorillas are considered the closest human relative after chimpanzees. To date, scientists distinguish between western (Gorilla gorilla) and eastern gorillas (Gorilla beringei), living in isolated populations in the corresponding regions of equatorial Africa. Western primates are divided into two subspecies - the western lowland gorilla (Gorilla gorilla gorilla) and the river gorilla (Gorilla gorilla diehli). The eastern group includes the Beringer gorilla (Gorilla beringei beringei) and the eastern lowland gorilla (Gorilla beringei graueri).
A team of biologists led by Richard Durbin of the Sanger Institute in Hinkston, UK, deciphered and analyzed the complete genome of the western lowland gorilla, and then compared it to that of humans and chimpanzees.
In their work, Darbin and his colleagues used DNA samples obtained from a female named Camila, who lives in the zoo in the American city of San Diego. In addition, biologists examined old samples that were extracted from the tissues of two other monkeys from the western population and one eastern lowland gorilla.
According to geneticists, the complete gorilla genome is made up of 3 billion nucleotides - the individual building blocks of DNA. It contains almost 21 thousand genes encoding proteins, and about 6.7 thousand regions containing "instructions" for the assembly of messenger RNAs.
Evolution of human relatives
After decoding the genome, the researchers compared its structure with the genome arrangement of other great primates - humans, common chimpanzees (Pan troglodytes), orangutans (Pongo abelii), and rhesus monkeys (Macaca mulatta). This allowed scientists to map the similarities and differences in the genomes of the closest human relatives and estimate the separation time of their ancestors.
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To the surprise of biologists, the human and gorilla genomes contained a significant number of similar regions - about 15% of the total genome length, which were very different from those in chimpanzee DNA. In addition, a similar number of genes make gorillas and chimpanzees related and distant from humans.
As biologists note, in the genomes of all three primates, the genes that are responsible for the functioning of the hearing aid and other sensory organs and control the development of the brain of the embryo and infants evolved most rapidly.
“We found that many of the gorilla's genes developed in parallel to their human counterparts, including the areas responsible for hearing. Many scientists believe that the rapid evolution of human hearing is associated with the development of articulate speech. Our work casts doubt on this assumption, since these genes changed at the same rate in both humans and gorillas,”explained team member Chris Tyler-Smith of the Sanger Institute.
According to the calculations of Darbin and his colleagues, the ancestors of humans and gorillas separated about 10 million years ago, and that of humans and chimpanzees 6 million years ago, which is broadly consistent with the time indicated by paleontology. The separation of western and eastern gorillas occurred approximately 1.75 million years ago, and it dragged on for a very long time. According to biologists, this process is similar to how chimpanzees and their pygmy "cousins" -bobo, as well as the ancestors of modern humans and Neanderthals separated from each other.