Scientists have found that eating the ancestors of the people in the time of dinosaurs

© Dr Mark Witton, a palaeo-artist, University of PortsmouthТак the artist imagined the ancient mammals that lived in England 145 million years agoScientists have found that eating the ancestors of the people in the time of dinosaurs© Dr Mark Witton, a palaeo-artist, University of PortsmouthПодпишись to daily updates RIA Science

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Genetics found in the DNA of human and all other mammals scraps genes for «digestion» of chitin, which clearly suggests that our earliest ancestors that lived at the end of the age of dinosaurs were insectivores, said in an article published in the journal Science Advances.

«Only insectivorous mammals feed exclusively on invertebrates, the five genes associated with the production of chitinase. This feature had, as shown by our study, and the first placental mammals. All of this suggests that beetles and other invertebrates formed the basis of the diet of our early ancestors,» said Christopher emerling (Emerling Christopher) from the University of California at Berkeley (USA).

The time of appearance of the first mammals still remains a mystery to paleontologists. Most scientists think that the first warm-blooded animals appeared 220 million years ago, in the middle of the Triassic period, along with the first primitive dinosaurs. It is not quite clear whether there were mammals on all continents in this era, or spread on Land after the extinction of the dinosaurs 65 million years ago.

The first primitive mammals, according to the structure of their teeth, had a relatively small size and ate ate monotonous, mostly insects and fruit. This has forced many scientists long enough to consider that the boom of their evolution began only after the dinosaurs, do not let furry «competitors» to occupy new ecological niches became extinct.

These animals, as noted by emerling, were not the direct ancestors of humans – almost all of them became extinct along with the dinosaurs, or were driven to the «edge of evolution» immediately after the start of the modern geological era. Their place was taken by the first placental mammals, which appeared much later, about 160-145 million years ago, as indicated by the remains of two ancient animals found in China in 2002 and 2011.

Most scientists believe that the first placental animals, as their marsupial cousins, ate mostly insects, but in this respect today there is a lot of controversy. Some paleontologists suggest that the transition to intrauterine development could allow our ancestors to master new niches before the extinction of dinosaurs and early Cenozoic boom of the evolution of mammals.

Genetic chronicle

Emerling and his colleagues tested these theories witty way. They suggested that if all mammals are descended from a carnivorous ancestor, then their DNA should have been retained at least traces of genes responsible for the digestion of chitin, the main component of the shell of all invertebrates.

Taking a sample of the CHIA gene, which plays a similar role in the body of the aardvark and other insect-eating mammals, scientists have tried to find its analogues in the DNA of over a hundred species of modern animals, including man, bears, elephants and other creatures do not feed on invertebrates.

As it turned out, the genomes of all placental mammals is present not just one, but five copies of this gene. In most animals almost all of these stretches of DNA are damaged, and only to armadillos, aardvarks and some lemurs eating only insects, all five genes are working.

A similar pattern, as noted by emerling, confirms the current view of paleontologists and allows you to calculate the approximate time of first appearance of herbivorous and carnivorous mammals. They, as shown by a comparison of the «scraps» CHIA, there were approximately 67, 56 and 53 million years ago, about 10 million years after the extinction of the dinosaurs.

This, again, corresponds to the data of the excavations and suggests that other «fossil» genes hidden in the DNA of animals and humans, will allow us to learn a lot about the evolution of life or to resolve other disputes related to the origin of man and other inhabitants of the Earth.

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