A new study suggests survival of the friendliest took place when humans became domesticated, starting at least 600,000 years ago. At that time, Homo sapiens split from the Neanderthals, Denisovans, and other hominids. (According to recent research into Dragon Man, the actual split may have taken place more like 948,700 years ago.)

Of course, that leads to the natural question: Who domesticated humans? Well, the only available conclusion (for mainstream scientists) is to assume humans domesticated themselves as they began domesticating other animals. Did we humans tame our own species? 

For whatever reason, as yet speculative, humans became less aggressive, friendlier, and more cooperative. For evidence, Science takes note that Homo sapiens also developed physical traits pointing to domestication. 

For example, the recently-discovered Dragon Man had a large brow ridge and skull, but our ancestors changed akin to changes in domesticated animals.

“Modern humans are also less aggressive and more cooperative than many of our ancestors. And we, too, exhibit a significant physical change: Though our brains are big, our skulls are smaller, and our brow ridges are less pronounced. So, did we domesticate ourselves?” writes Michel Price.

Possibly, domestication is an explanation for why we look so different from early humans.

Fewer Stem Cells 

In domesticated animals, traits like floppy ears and smaller teeth are linked to fewer neural crest stem cells. As University of Milan molecular biologist Giuseppe Testa knew, a gene called BAZ1B is related to neural crest cells. Moreover, people with a rare genetic condition called Williams-Beuren syndrome are known to be missing one copy of the BAZ1B gene (Most people have two copies).

So, the researchers studied cultured neural crest stem cells from ordinary people as compared to those with Williams-Beuren or with duplicates of the BAZ1B gene. Then, they examined BAZ1B-sensitive genes in modern humans and our ancient relatives.

“When the researchers looked at those hundreds of BAZ1B-sensitive genes in modern humans, two Neanderthals, and one Denisovan, they found that in the modern humans, those genes had accumulated loads of regulatory mutations of their own. This suggests natural selection was shaping them,” Science reports. 

Of course, in this case, the natural selection process seems to have been self-directed.

Self-Domestication

After the study, scientists suggest humans became domesticated by a genetic process similar to other animals. 

“And because many of these same genes have also been under selection in other domesticated animals, modern humans, too, underwent a recent process of domestication, the team reports today in Science Advances.”

Thus, humans selected friendly animals and possibly friendlier mates for themselves. However, it’s unclear how that took place.

According to University of Vienna evolutionary biologist William Tecumseh Fitch III, it may have been due to cultural changes as people came together in cooperative communities. Due to the changes, being an aggressive Alpha male was no longer required or desired, perhaps.

“There was active selection, for the very first time, against the bullies and the genes that favored their aggression,” he adds. But so far, “Humans are the only species that have managed this,” said Fitch.

Are humans unique as the only species to self-domesticate, favoring less aggression? It’s something to ponder as you consider all the bullies and lone wolves you know. Unfortunately, between 2016-2019, American society saw a 35% rise in bullying behavior.

See also: Scientists Discover a Switch Causing a Gorilla’s Brain to Grow More Like a Human’s

Another idea is that our close bonds with the first dogs shaped our own behavior, an interspecies convergent evolution or symbiosis.

See more about how humans and dogs evolved together from Moth Light Media:

There is another idea, although scorned by most scientists and academics. Ancient Astronaut theorists would say that human domestication could have resulted from tinkering by extraterrestrials. In the distant past, beings from elsewhere tinkered with our genes to create a more subservient, compliant human. Therefore, they domesticated us the same as we later domesticated the animals. Although unproven, this is a story they will no doubt find quite interesting.

Friendly ‘Elfin’ Humans and Domestication

The new study builds off earlier research into domesticated dogs. Interestingly, Princeton University geneticist Bridgett vonHoldt gained insight by examining humans with a rare genetic disorder.

In 2017, scientists released research into why dogs are hypersocial compared to much more aloof wolves. To find out, VonHoldt focused on genes in “elfin” humans with Williams-Beuren syndrome caused by deletions and variable disruptions of portions of chromosome 7. In dogs, the region is on dog chromosome 6, so she started there.

After studying a group of 18 dogs and 10 captive wolves, the team found that, indeed, hypersocial behavior in dogs was related to DNA disruptions in canine chromosome 6.

“We’re almost describing variation in personality,” in the animals, VonHoldt pointed out.

“Disruption on a gene for a protein called GTF21, which regulates the activity of other genes, was associated with the most social dogs. A relative lack of changes in that gene seems to lead to aloof, wolflike behavior,” she said.

According to evolutionary anthropologist Brian Hare from Duke (not involved in the work):

“The study is exciting because it provides such strong support for the ‘survival of the friendliest’ hypothesis of dog domestication,” said Hare. Due to the gene disruptions, “fear was replaced by friendliness.”

Thus, though not certain, the study indicates that social behaviors in humans and dogs are related to analogous genes.

In the video below, Science explains that “ancient genetic engineering may be why you’re pooch loves to see you come home every day.”

Video from Science Magazine:

Williams Syndrome 

Notably, those with Williams-Beuren may be trusting, friendly and have changed facial features. However, each person is unique. In some cases, they may have small, upturned noses, a wide mouth, widely spaced eyes, and full lips. For some, there may be a “starry pattern” in the iris.

While autism may be one symptom, it coincides with an “excessively social” predisposition. According to estimates, 1 in 7,500 to 20,000 people have Williams-Beuren syndrome. Interestingly, scientists know it can be inherited but also develops spontaneously. Sometimes, people can live most of their lives without knowing they have Williams syndrome, as you can see in the video below.

On the whole, it appears individuals with Williams syndrome are often happy, love life and being with people.

More about Williams Syndrome from WWLP22:

Featured image: Image by Kristendawn via Pixabay, Pixabay License with silhouette by StockSnap via Pixabay, Pixabay License