The evolution of mankind has not stopped, and it pushes men toward increasing body weight and deteriorating education, and women – toward “medium” growth and early onset of puberty, the geneticists state in the article of the journal PNAS.
“We found a very obvious link between the number of offspring and certain features of the anatomy and appearance of men and women.For example, men with a high body mass index produce more children than their more slender” competitors. “Similarly, high women leave fewer children than representatives of the weaker sex with a medium height, “- write Peter Visscher from the University of Queensland in Brisbane and his colleagues.
In recent years, scientists fiercely argue about whether the evolution of people stopped after the emergence of the first civilizations and their representatives moved to life in large societies like themselves.
Some biologists claim that the biological evolution of Homo sapiens has slowed or even stopped, as the survival of individuals and their likelihood of continuing their genes has become dependent not on the quality of genes, but on ingenuity, wealth and social status.
Other scientists disagree with this, and over the past twenty years they have conducted several experiments and studies in which biologists have tested how the genome of mankind as a whole has changed over the past centuries and millennia. They often led to directly opposite conclusions, which did not add confidence that evolution was continuing or that it had stopped.
Visscher and his colleagues tried to find traces of natural selection among several thousand Britons who donated their DNA to the Biobank project. Scientists were interested in how various small variations in genes and distinctive features of anatomy and appearance can affect the number of their children.
Carrying out a similar comparison, genetics were guided by a simple principle – genes of people leaving more offspring are more likely to survive and spread beyond the population than DNA of men and women with only one child or not having children at all.
Guided by this idea, scientists analyzed the DNA of approximately 500,000 people aged 50 to 70 who participated in the Biobank research, and identified about a dozen features of their appearance and anatomy, as well as related genes that influenced their reproductive success .
To do this, the scientists calculated the typical number of children characteristic of a given set of Britons, and compared it with how many offspring in people of high stature or low body weight. Any deviations from the “norm” indicated that Visscher and his team are dealing with the consequences of two types of natural selection – stabilizing or directed.
The first type of selection is associated with the existence of a kind of “golden mean”, for example, the ideal growth of a woman whose possessor will have the maximum success in procreating. The second works on the principle of “more is better” or “more is worse”: the earlier a woman gives birth to the first child, the fewer children she has on average. Similarly, the number of offspring was affected by the level of education, which confirms the recent findings of geneticists who observed the evolution of the inhabitants of Iceland.
The study of these factors, as scientists hope, will help evolutionists understand what is controlling today’s human evolution, and what social factors, such as poverty, access to food and education, can influence its course the most.