All modern mammals, from the Utconos to the blue whale, have come from a common ancestor who lived about 180 million years ago, but the international group of researchers has reconstructed it using computer technology, and the results of the study are published in Proceedings of the National Academy of Sciences.
The results of the study are important for understanding the evolution of mammals and for efforts to preserve them.
Researchers used high-quality genome sequences of 32 living species, representing 23 of the 26 known mammals, including humans and chimpanzees, vombates and rabbits, lamentins, livestock, rhinoceros, bats and pangolins, and including the chicken and Chinese alligator genomes as comparison groups, some of which are produced by the Earth BioGenome Project and other large-scale biodiversity genome sequence projects.
The reconstruction showed that the ancestor of the mammal had 19 autosomal chromosomes, which are responsible for inheriting the characteristics of the body beyond those controlled by the sexy chromosomes , plus two sex chromosomes.
Biologists have identified 1,215 units of genes that consistently occur on the same chromosome in the same order in all 32 genomes. According to scientists, these building blocks of all mammals' genomes contain genes that are crucial to the development of a normal embryo.
The researchers also found nine complete chromosomes or chromosomes in an ancestor mammal whose gene order is the same as in the chromosomes of modern birds. The study shows the evolutionary stability of order and gene orientation on chromosomes over a long period of evolution of more than 320 million years.
On the contrary, the areas between these conservative blocs contained more repetitive sequences and were more prone to breakdowns, restructurings and duplications of sequences, which are the main drivers of the evolution of the genome.