An increase in brain volume is the result of a genetic malfunction, for which the king of nature pays with schizophrenia.
The reasons why man quickly moved out of the animal kingdom and turned into a rational being were still incomprehensible to scientists. Some 3 million years ago, we were no different from other primates. Our ancestors rode in trees and had a brain volume of 330-400 cubic centimeters - exactly the same as that of modern chimpanzees. However, then something strange happened in the group of our ancestors, who are called Australopithecus: in a short period of time by historical standards - 1 million years - the brain volume increased 3-4 times and reached almost modern values (1200 cubic cm and more). This rapid evolution can be traced very well in the fossil record.
The pituitary gland was not responsible for the humanization of Sharikov
What happened? A team of geneticists under the leadership of Professor Pierre Vanderhagen from the Free University of Brussels (Belgium) undertook to reveal this secret. Scientists have suggested that the enlargement of the brain is associated with a mutation of genes that are turned on during the developmental stage of the embryo. Because that's when the key stages of brain formation take place.
Professor Vanderhagen and his colleagues began to look for specific genes that humans have, but other animals lack. It turned out that contrary to Bulgakov's "Heart of a Dog", it is not the pituitary gland that is responsible for humanization, but a special family of genes codenamed NOTCH2NL. It is a variant of the ancient NOTCH gene that is present in all animals and regulates the number of neurons in the brain.
Schizophrenia - grief from the mind
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But people were extraordinarily lucky: once our common ancestor with the apes accidentally duplicated NOTCH while copying DNA. But this version of the gene turned out to be inoperative. It is still present in gorillas and chimpanzees, but does not manifest itself in any way. But in Australopithecus 3 million years ago, another erroneous duplication of a DNA fragment happened and the same NOTCH2NL turned out, which played the role of a powerful intellectual doping. The new gene has caused an explosive growth in the number of neurons and an increase in the cerebral cortex - the part of our "attic", which is responsible for the ability to speak, creative thinking and creativity. The same genes were found in our Neanderthal and Denisovan cousins.
However, the rapid evolution of the brain also has a dark side. Vanderhagen and his colleagues believe that 3 million years of evolution is too short for the new genes responsible for humanization to work perfectly. It turned out that they are to blame for such disruptions in the development of the brain, such as microcephaly (a decrease in the size of the skull and brain) or macrocephaly - on the contrary, its excessive increase. In addition, Belgian scientists believe that it was this genetic revolution that led to the emergence of diseases such as schizophrenia and autism in humans.
YAROSLAV KOROBATOV