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Representation of a Neanderthal, one of the five archaic human groups. Source: regis allouet /Adobe Stock

Modern Humans Interbred With At Least Five Archaic Human Groups

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Genetic analysis has revealed that the ancestors of modern humans interbred with at least five different archaic human groups as they moved out of Africa and across Eurasia.

While two of the archaic groups are currently known -- the Neandertals and their sister group the Denisovans from Asia -- the others remain unnamed and have only been detected as traces of DNA surviving in different modern populations. Island Southeast Asia appears to have been a particular hotbed of diversity.

A Neandertal. (procy_ab /Adobe Stock)

A Neandertal. ( procy_ab /Adobe Stock)

Published in the Proceedings of the National Academy of Sciences (PNAS) , researchers from the University of Adelaide's Australian Centre for Ancient DNA (ACAD) have mapped the location of past "mixing events" (analyzed from existing scientific literature) by contrasting the levels of archaic ancestry in the genomes of present-day populations around the world.

Archaic Human Genes Survive in Modern Humans

"Each of us carry within ourselves the genetic traces of these past mixing events," says first author Dr. João Teixeira, Australian Research Council Research Associate, ACAD, at the University of Adelaide.

"These archaic groups were widespread and genetically diverse, and they survive in each of us. Their story is an integral part of how we came to be. For example, all present-day populations show about 2% of Neandertal ancestry which means that Neandertal mixing with the ancestors of modern humans occurred soon after they left Africa, probably around 50,000 to 55,000 years ago somewhere in the Middle East."

But as the ancestors of modern humans travelled further east they met and mixed with at least four other groups of archaic humans.

Representation of archaic humans. (anibal /Adobe Stock)

Representation of archaic humans. ( anibal /Adobe Stock)

Island Southeast Asia was a Crowded Place…

"Island Southeast Asia was already a crowded place when what we call modern humans first reached the region just before 50,000 years ago," says Dr. Teixeira. "At least three other archaic human groups appear to have occupied the area, and the ancestors of modern humans mixed with them before the archaic humans became extinct."

At least three other archaic human groups appear to have occupied the area, but they are still a mystery. (Kovalenko I /Adobe Stock)

At least three other archaic human groups appear to have occupied the area, but they are still a mystery. ( Kovalenko I /Adobe Stock)

Using additional information from reconstructed migration routes and fossil vegetation records, the researchers have proposed there was a mixing event in the vicinity of southern Asia between the modern humans and a group they have named " Extinct Hominin 1 ."

The Out of Africa Story Isn’t a Simple One

Other interbreeding occurred with groups in East Asia, in the Philippines, the Sunda shelf (the continental shelf that used to connect Java, Borneo, and Sumatra to mainland East Asia), and possibly near Flores in Indonesia , with another group they have named "Extinct Hominin 2."

"We knew the story out of Africa wasn't a simple one, but it seems to be far more complex than we have contemplated," says Dr. Teixeira.

"The Island Southeast Asia region was clearly occupied by several archaic human groups, probably living in relative isolation from each other for hundreds of thousands of years before the ancestors of modern humans arrived. The timing also makes it look like the arrival of modern humans was followed quickly by the demise of the archaic human groups in each area."

The arrival of modern humans was followed quickly by the demise of the archaic human groups in each area. (Kovalenko I /Adobe Stock)

The arrival of modern humans was followed quickly by the demise of the archaic human groups in each area. ( Kovalenko I /Adobe Stock)

Top Image: Representation of a Neanderthal, one of the five archaic human groups. Source: regis allouet /Adobe Stock

The article, Out of Africa and into an archaic human melting pot was originally published on Science Daily.

Source: University of Adelaide. "Out of Africa and into an archaic human melting pot." ScienceDaily. ScienceDaily, 15 July 2019.

References

João C. Teixeira, Alan Cooper. Using hominin introgression to trace modern human dispersals .’ Proceedings of the National Academy of Sciences , 2019; 201904824 DOI: 10.1073/pnas.1904824116

Comments

Closed-minded 'scientists', which there are many, state theories as facts far too often. How many times have their teachings been as facts, only to discover they were incorrect? That means admitting 'wrong'. I have no problem admitting wrong; I can then move along and hopefully learned something in the process. "HIstory" is what we have and "history" doesn't exist without subjectivity and agendas.

Most of my beliefs are based upon bits of information and my own personal views via discovery.

I tend to agree. That, or other hominin groups evolved separately, though this seems less likely. Another possibility, is that we were one of the last to leave Africa. Perhaps we were the last to evolve?

But honestly, this feels like vindication to me, I've long suspected that there were more than just us, Neanderthals and Denisovans. Three more groups! I love when we find evidence to suggest that our past was far more interesting than we've previously thought.

Gary Moran's picture

Hmmmm! So, if modern Homo Sapiens originated in Africa, and then migrated, what or where are the supposed origin(s) of the other ‘archaic’ beings they mated with? Perhaps the earliest ancestors did not really begin in Africa, but somewhere else and then they migrated to Africa and began to evolve to Homo Sapiens.  

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