An international team of scientists has identified the genetic mechanisms of the evolution of ruminants from deer to cattle by identifying rearrangements in chromosome hotspots. An article about this was published in the journal Genome Research, belonging to the first quartile.
The method made it possible to establish how the chromosomal rearrangement took place in ruminants - in other words, how genes changed in hot spots (this is the name of the chromosome regions that undergo transformation during evolution, in contrast to cold spots that keep gene blocks intact). It turned out that these changes affect the regulation of whole groups of physiologically important genes, in particular those responsible for digestion, which is characteristic of the entire suborder of ruminants belonging to the order of artiodactyls and distinguishes them from other animals.
“Ruminants have a complex digestive system, which has become so in the process of evolution. It is known that the ancestors of all mammals are insectivores, having much in common with predators. They practically do not chew food, they digest very quickly, so they need to eat often. In ruminants, the digestion process is much longer, the stomach consists of four sections, and digestion takes place in four stages. Although, probably, ruminants once ate "what runs". And today a deer lives in Southeast Asia - the smallest and most ancient ruminant in the world - it eats crabs and mice. In the news that came out recently, the musk deer was ranked as predators, but despite the presence of tusks, it feeds exclusively on plant foods, in particular leaves and moss, "says the co-author of the article. Head of the scientific direction of the Institute of Molecular and Cell Biology of the Siberian Branch of the Russian Academy of Sciences, Doctor of Biological Sciences Alexander Sergeevich Grafodatsky. Under his leadership, the genomes of artiodactyls in the Novosibirsk Academgorodok began to be studied almost 40 years ago.
Today, the method of chromosome painting (ZooFISH) is used to study genomes at the IMKB SB RAS. It got this name due to the fact that chromosomes are stained with fluorochromes - dyes that can glow in ultraviolet or blue radiation. This is done in order to compare chromosome regions in different species and determine which of them have remained unchanged in the process of evolution, and which have undergone rearrangement. The method, in combination with sequencing and bioinformatics data obtained abroad, made it possible to determine with great accuracy the chromosomal rearrangements of the most important for evolution of representatives of cetaceans, which include ruminants. The chromosomes of alpaca, gray whale, javan deer, Siberian musk deer, giraffe, fallow deer, Siberian roe deer, black antelope, musk ox and cow were examined.
“We have received extremely interesting results, many of them are still awaiting confirmation, in particular, there is reason to believe that the same chromosomal rearrangements that are responsible for changes in the type of digestion are also associated with the characteristics of childbirth,” notes Alexander Grafodatsky.