Study: The emergence of patriarchy led to a reduction in genetic diversity among men

Researchers believe that the lack of genetic diversity among men may not have arisen due to military conflicts, but rather as a result of a radical transformation in human society and the transition to patriarchy after the emergence of civilization.

Nature Communications magazine indicates that, according to French paleontologists and anthropologists, the significant decline in genetic diversity among men, which occurred 3-5 thousand years ago, was not related to the abundance of wars, but rather to the emergence of the patriarchal system and the formation of clan societies of closely related men.

The researchers say: “Our calculations showed that social and economic factors influenced the level of genetic diversity among men much more than wars and other manifestations of mass violence in the Copper Age, and can fully explain why the level of genetic diversity among women in this era was about 17 times higher than in the Copper Age. The same indicator for men.

This conclusion was reached by a team of French paleontologists and anthropologists headed by Raphael Chi, a researcher at Paris City University, during his study of the reasons for the sharp decline in the level of genetic diversity among men about 3-5 thousand years ago. As is known, many historians believe that this is due to the large number of wars during the Copper Age, which claimed the lives of up to 20-30 percent of each generation.

Based on this, researchers assume that this genetic bottleneck may not have arisen due to military conflicts, but as a result of the radical transformation of human society and the transition to patriarchy after the emergence of civilization. The evidence is that men in African pastoralist and farmer tribes are inferior to women in terms of genetic diversity without participating in any wars, which is unusual for hunter-gatherer societies.

Guided by similar scenarios, the researchers calculated how the level of genetic diversity in humans would change in two scenarios, one in which societal power and property were transmitted through the paternal and maternal lines, and the other only through the male line. The scientists calculated how the gene pool of several villages in both cases changed over nearly 20,000 generations, and also analyzed how various factors, including wars, affected it.

Scientists' calculations showed that the level of men's genetic diversity was not greatly affected by wars, but rather by two social factors - the rate of "separation" of new clans from existing large families, as well as differences in social and reproductive status between kinship groups of men, which led to an increase in the size of some clans and the disappearance of others.

According to scientists, certain combinations of these two factors have led to decreased genetic diversity among men in patriarchal societies, even in cases where the men have never participated in wars. But mass violence accelerated this process, causing genetic diversity among men to decline several dozen generations faster than in the peaceful scenario.

Scientists believe that these results indicate that many historians overestimate the impact of wars and the mass migrations they caused on the genetic structure of humans in the Copper Age and subsequent civilizational eras, and underestimate the impact of social and economic factors on human reproductive behavior.