by Sergei SAVELYEV, Dr. Sc. (Biol.), Head of the Department of Embryology, Institute of Human Morphology, Russian Academy of Medical Sciences Medical statistics has fixed a steady increase in the incidence of congenital abnormalities of the brain all over the world. Neural disorders are responsible for 60-65 percent embryonal and fetal mortality. What are the causes of this increase? We have no exhausting answer to this question yet, but we can assert that the problem will become more clear after deciphering of mechanisms regulating the formation of the nervous system. This was the subject of the interview of our correspondent Sergei Popov with Sergei Savelyev, a specialist in embryonal development, Doctor of Biological Sciences. —  Sergei Vyacheslavovich, you have probably heard an opinion that genetic failures, largely caused by deterioration of ecological situation, are "responsible" for the increase in the incidence of intrauterine pathologies ? —  This is not the only reason fixed by statistics. Of course, our notions have advanced considerably since the Middle Ages, when the time of entering of the psyche into the human embryo was an object of ardent discussions, as its presence was assumed to guarantee normal development. In late 19th and early 20th centuries embryonal death and spontaneous abortions were attributed solely to infections. Later on there predominated ideas of hormone defects. For the last decades the focus on genetic determination led to predominance of another viewpoint: the entire ontogenesis was considered as a linear realization of the genetic program, and its disorders were assumed to be responsible for deviations. However, this hypothesis was not confirmed: the actual percentage of genetic defects in human embryos with pathologies does not exceed 10 percent, 5 percent are caused by infections and toxins, while the causes of 85 percent of them, i.e. the greater part of all neural disorders, remain a mystery. Accordin ... Читать далее