Human hair, bird feathers and scales of modern reptiles, no matter how much they did not differ in appearance and functions appeared to have a common origin — they formed from the scales of ancient reptiles. To such conclusion the group of geneticists under the leadership of Michel Milinkovic at the University of Geneva, and helped them in this study such a phenomenon as baldness.
The researchers say that in a scientific discussion about the origin of the human hair they were “involved” polyleucine. Attention Michel Milinkovic has attracted sold in the market bearded Agama with a rare mutation — she had no scales. A scientist has acquired a “bald” reptile to explore the genetic nature of such features of the animal.
After analyzing DNA purchased Agama, a scientist together with his colleagues discovered she had a gene mutation ectodysplasin-A. interestingly, the same gene, as has been known earlier, at a similar mutation leads, in particular, to the balding man and mice. This led researchers to believe that between the scales and the hair may be more common than expected. To ensure that this is so, the scientists decided to double-check one of the main arguments in favor of the fact that the hair did not come from scales.
Until now it was widely believed that hair and feathers evolved from placodal — a kind of dense growths formed on the skin of the embryo. Because reptiles such was not observed, the researchers concluded that this thickening has occurred in mammals and birds after the process of evolution they have “separated” with reptiles. It was assumed that appear placode in birds and mammals become independent from each other. However, carefully tracing the embryonic development of bearded Agamas, and also some crocodiles and snakes, the scientists came to the conclusion that placode on the future of the scales are formed and they have, albeit very briefly. The mutation of the gene ectodysplasin-And in one of the chromosomes has led to the fact that animals are born with reduced scales, and in both — that placode they have not formed, and the light they appear “bald”.
Their work, scientists published in the journal Science Advances.Related posts: