The gorilla genome
Part of the gorilla genome is closer to humans than to chimpanzees, scientists have found
Comparative genealogyGorillas are considered the closest relative of humans after chimpanzees.
To date, scientists have identified western (Gorilla gorilla) and eastern gorillas (Gorilla beringei) living in isolated populations in the corresponding areas of equatorial Africa. Western primates are divided into two subspecies – western lowland gorillas (Gorilla gorilla gorilla) and river gorillas (Gorilla gorilla diehli). The eastern grouping includes the Beringer gorillas (Gorilla beringei beringei) and the eastern lowland gorillas (Gorilla beringei graueri).
A group of biologists led by Richard Durbin from the Sanger Institute in Hinkston (UK) deciphered and analyzed the complete genome of the western lowland gorilla, and then compared it with the genomes 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 of the American city of San Diego. In addition, biologists studied old samples that were extracted from the tissues of two other monkeys from the western population and one eastern plains gorilla.
According to geneticists, the complete gorilla genome consists of 3 billion nucleotides – individual "bricks" of DNA. It contains almost 21 thousand genes encoding proteins, and about 6.7 thousand sites containing "instructions" for the assembly of informational RNAs.
Evolution of human relativesAfter decoding the genome, the researchers compared its structure with the structure of the genomes of other higher primates – humans, common chimpanzees (Pan troglodytes), orangutans (Pongo abelii), and rhesus monkeys (Macaca mulatta).
This allowed scientists to map similarities and differences in the genomes of the closest human relatives and estimate the time of separation of their ancestors.
To the surprise of biologists, the genomes of humans and gorillas contained a significant number of similar sites – about 15% of the total length of the genome, which were very different from similar ones in the DNA of chimpanzees. In addition, a similar number of genes are related to gorillas and chimpanzees and separates them from humans.
According to biologists, in the genomes of all three primates, the genes responsible for the operation of the hearing aid, other sensory organs and controlling the development of the brain of the embryo and infants evolved the fastest.
"We found that many gorilla genes developed in parallel with 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 one of the group members Chris Tyler–Smith from 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 humans and chimpanzees – 6 million years ago, which generally corresponds to the time indicated by paleontology.
The separation of western and eastern gorillas occurred about 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 dwarf "cousins"-bonobos, as well as the ancestors of modern humans and Neanderthals separated from each other.
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13.03.2012