Cro-Magnon women could not give birth to boys from sex with our closest relatives
It is believed that the last Neanderthals became extinct 25 thousand years ago. Contrary to popular belief, they were not our ancestors, but were cousins. That is, half a million years ago we had common parents, but then the paths of the Neanderthals and Cro-Magnons (these are our immediate ancestors) diverged. These two kinds of people waged an uncompromising war among themselves for resources. However, from time to time, romantic relationships arose between them.
Moreover, mixed marriages were such a widespread practice that the DNA of every European or Asian resident still contains from 1% to 3% of the genetic material of Neanderthals. Only Africans did not have sex with Neanderthals - their DNA does not contain traces of crossing. Why are our brothers in reason extinct? There are many versions on this score.
NEANDERTALS KNOWLEDGE AMPUTE LIMBS
A popular hypothesis was that Neanderthals lagged behind our ancestors in intellectual development. Supporters of this version relied, in particular, on the fact that their childhood was very short. Sexual maturity was reached by the age of 8-10. It was different with people. The 12-year-old Cro-Magnon child looked like the same age as the 8-year-old Neanderthal. Cro-Magnons remained children longer, which means that the period of study took a long time and allowed them to accumulate more knowledge and experience.
However, recent discoveries have refuted the thesis of the backwardness of the Neanderthals. So in the Shanidar cave (Iraq), the burial of a 45-year-old Neanderthal man was found. His right arm was amputated above the elbow when he was young. The fact that he survived speaks of great knowledge in medicine, as well as a high level of mutual assistance: his fellow tribesmen did not leave the cripple in trouble. There is an interesting statistics: 36 Neanderthals are known to have traces of bone fractures. Of these, only in 11 cases modern doctors recognized the results of treatment as unsatisfactory. The efficiency of medical care was over 70%.
In addition, there are known drawings of Neanderthals depicting an elk and a leopard (which means they had abstract thinking). Neanderthals, like humans, had their own religion, they believed in an afterlife: traces of a large number of flowers and food were found in the burials. They created stone tools and used short spears to hunt. Judging by the structure of the vocal apparatus, they had a language that consisted mainly of consonants (clicking consonants) and a small number of vowels. Such variants are also found in the languages of the modern African tribes of the Bushmen and Hottentots. In addition, the Neanderthal man has a speech gene FOXP2 with the same modification as in humans.
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In open combat, the Neanderthals were difficult to defeat. But all ancient people had another common and terrible enemy - hunger
PEOPLE BELIEVED HUNGER EASIER
Another assumption explains the victory of the ancestors of modern man by the fact that our body used "fuel" more economically. Neanderthals were inferior in height to Cro-Magnons by an average of 15 cm (165 cm for them, against 180 for us). However, they had an incredibly powerful physique. Neanderthals had 30-40 percent more muscle mass than humans. And physically they, of course, were much stronger. However, every virtue has a downside. Anthropologists calculated that due to their dense build and short limbs (they had to take many small steps to catch up with the long-legged Cro-Magnon man), the energy costs of movement for Neanderthals were 32 percent higher!
In addition, a group of American scientists using computer simulations determined that the body of a Neanderthal under similar conditions consumed about 350 more calories daily than the body of a Cro-Magnon. This is quite a lot, considering that the daily intake of a modern person is 2,400 calories.
In open combat, the Neanderthals were difficult to defeat. But all ancient people had another common and terrible enemy - hunger. It regularly appeared when, due to climate change, vegetation changed and this forced the animals that our ancestors hunted to migrate. And here the "energy-saving" organism of the Cro-Magnon man had a huge advantage. What is a Tribe of 30 Savings of 350 Calories? This means that the Cro-Magnons still had additional resources to feed 7 (!) Children under the age of 4 (they need about 1300 calories per day). And the children of the Neanderthals died from malnutrition. And in the end, the Cro-Magnons destroyed physically strong competitors with the help of a population explosion.
NEANDERTHALS REMAINED WITHOUT HEIRS?
But the most recent study by Stanford University geneticists under the direction of Carlos Bustamante puts forward a completely new version of the decline of the Neanderthals.
Scientists have studied the DNA of 12 Neanderthals who lived 49 thousand years ago in the El Sidron cave in Spain. They were primarily interested in the Y-chromosome - it is she who contains the gene that is responsible for the development of the body according to the male type. As you know, in men, cells contain two sex chromosomes - X and Y. And women have only two X chromosomes.
Recall that geneticists knew that Europeans inherited from Neanderthals from 1% to 3% of the genes. But, to their amazement, it turned out that our male Y chromosome has no trace of mixing with Neanderthals. This means that all inheritance occurred along the female line, through the X chromosome!
Experts believe that the reproductive systems of the Neanderthal man and the modern woman did not quite match each other. Only girls could be born in mixed families. Neanderthals possessed mutations that elicited an immune response in a pregnant woman if she was carrying a male child. That is, there was a reaction of rejection, which is observed in patients when they receive a donor organ transplant. As a result, pregnancy in women inevitably ended in miscarriage. We can say this with confidence, since the genes of the Neanderthals were not able to gain a foothold in our male sex chromosome.
Together with other factors, this circumstance led to the disappearance of the Neanderthals.
Yaroslav KOROBATOV
