Homo Sapiens had to pay a high price for their intelligence: scientists found out what it was 0 20

The author of the study, Ilan Libedinsky from the Center for Neurogenomics and Cognitive Research in Amsterdam, believes that along with intelligence, humans developed a tendency towards mental disorders, writes New Scientist.

"Mutations associated with mental disorders apparently affect a part of the genome that is also responsible for intelligence. So there is an intersection here. Progress in cognitive functions may have come at the cost of increasing our brain's vulnerability to mental disorders," said Libedinsky.

It is known that Homo Sapiens separated from chimpanzees and bonobos more than 5 million years ago. Since then, the human brain has tripled in size. The fastest growth of the human brain was observed in the last 2 million years.

Fossils allow scientists to learn about the size and shape of our ancestors' brains, but they cannot tell what their brains were capable of. In the framework of new DNA research, scientists were able to determine which mutations in the genome may be associated with intelligence, brain size, height, as well as various types of diseases.

Specific aspects of mutations that indicate when they appeared in the human genome were also analyzed.

Libedinsky and his team combined two datasets to create an evolutionary chronology of human genetics related to the brain. The team investigated the evolutionary origins of 33,000 genetic variants found in modern humans and associated with a wide range of traits, including brain structure, various indicators of cognitive abilities and mental illnesses, as well as physical and health-related characteristics.

Most of these mutations appeared approximately 3 million to 4,000 years ago, with an explosive phase occurring in the last 60,000 years. According to experts, this was when humans migrated en masse out of Africa.

Mutations associated with more advanced intelligence appeared relatively recently. For example, mutations related to fluid intelligence (logical thinking) emerged on average about 500,000 years ago. This is 90,000 years later than mutations associated with cancer and nearly 300,000 years later than mutations related to metabolic functions and disorders.

Following these mutations, mutations associated with psychiatric problems appeared. This occurred around 475,000 years ago.

A similar situation repeated itself about 300,000 years ago when the shape of the cerebral cortex responsible for higher-order cognitive functions changed. In the last 50,000 years, numerous mutations related to language emerged, followed by mutations associated with alcohol dependence and depression.

"Mutations related to the most basic structure of the nervous system arise slightly earlier than mutations responsible for cognitive functions or intelligence, which makes sense, as the development of a higher level of intelligence requires the brain to develop first. Then the mutation responsible for intelligence arises before mental disorders, which also makes sense. One must first be intelligent and have language before disorders in these abilities arise," summarized the study's author.

Such a chronology, according to experts, also aligns with the idea that Homo sapiens acquired some mutations related to alcoholism and mood disorders from interbreeding with Neanderthals.

So far, scientists cannot say why evolution did not eliminate such mutations; perhaps their impact was not too critical, and in some cases even provided advantages.