Neanderthals possibly extinct because of sex, not violence

There is a small amount of evidence suggesting Neanderthals did not inherit human genes, despite the fact that about 2% of the genomes of all living humans outside of Africa come from Neanderthals. According to a recent study, the number of Neanderthals who may have reproduced sexually with one another decreased as a result of possible interbreeding with our forebears. Their final demise would have resulted from that.

May be a coincidence

Since just 32 Neanderthal genomes have been mapped thus far, it is possible that the absence of Homo sapiens DNA in their genes is a coincidence. However, the scientists disagree and believe that as technology advances, more genomes will become accessible, allowing them to clearly test their idea.

The new study's author, Professor Chris Stringer of the British Natural History Museum, explains: "Because Neanderthals frequently mated with Homo sapiens, we believe that their sexual conduct may have contributed to their extinction. As a result, they became less common until they completely vanished."

Tricky chatter

The two species must have had significant variations from one another, making communication challenging. Given the length of time they were apart, the linguistic gap is most likely considerably more than we can fathom and is greater than any language that exists today, according to Stringer.

Differences in brain and voice usage would have made the language barrier even more severe. There are 600 genetic differences between Neanderthals and humans, mostly in the vocal and facial regions. The large eyebrows and flat forehead of Neanderthals are a well-known example, which they may have also used for communication.

Crossing

Regardless matter how they interacted, these interactions caused the two species to crossbreed. However, these early contacts did not give rise to the Neanderthal genes that we still carry today. That didn't occur until much later, perhaps 60,000 years ago, when modern people went considerably farther.

It remains to be seen if the interbreeding of the species was fully voluntary. There may have also been aggressive sexual contact. Our closest cousins, the chimpanzees, have been observed engaging in both voluntary sex and violent conduct during interactions between two separate groups.

Neanderthals and Homo sapiens: refreshing it up

Around 600,000 years ago, the two species split off and developed in completely different parts of the globe. Neanderthal fossils have been discovered as far south as Siberia in Asia and Europe. In a climate that was much colder than it is now, they lived there for at least 400,000 years.

Our own ancestors, meanwhile, developed in Africa. It is unknown if they were a mix of many populations that lived dispersed across the continent or whether they were descended directly from an old African human race. According to genetic evidence, the two species came into contact for the first time around 250,000 years ago when Homo sapiens left Africa in search of food.

Zero human DNA

Because the species could only have progeny if a male Neanderthal shared a bed with a female Homo sapiens and not the other way around, no human DNA has been found in Neanderthals. Living humans may not have mitochondrial DNA, which was passed down from female Neanderthals. However, it's possible that males descended from the Neanderthal and Homo sapiens genus were less fertile than females.

The beginning of the end

Thus, a number of circumstances contributed to the extinction of the Neanderthals, including the fact that, due to their terrible living conditions, they already lived in tiny groups dispersed over a broad area, and that they interacted more with Homo sapiens than with one other. They were eventually exterminated as a result of the mingling of the two species and perhaps decreased fecundity.

As a result, Stringer says, "We don't know if the genes just went one way, because mating simply didn't happen, because it did happen but wasn't effective, or if the Neanderthal genomes we have are not representative." Follow-up research could concentrate on similar questions about other human species, such as the Denisovans, so we can get a better understanding of how our species interacted with our closest relatives. "If we can analyze more Neanderthal genomes we will be in a better position to determine if DNA from Homo sapiens went to Neanderthals as well."