Posted on 01/31/2020 12:31:26 PM PST by Red Badger
(Michael Brace/Flickr/CC BY-NC-ND 2.0)
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Deep inside our DNA lurks a legacy of lust and romance between estranged human bloodlines reconnecting on an epic journey around the globe. It now seems we might have been misreading key details in this erotic tale.
A new method for analysing our genomes for traces of Neanderthal genes has revealed modern African populations – long assumed to be Neanderthal-free – also have a mixed heritage after all.
"This is the first time we can detect the actual signal of Neanderthal ancestry in Africans," says geneticist Lu Chen from Princeton University in the US.
"And it surprisingly showed a higher level than we previously thought."
The finding has implications for how we interpret previous studies on the spread of genes that entered our family tree while we were still migrating across the Asian continent.
Initial findings on Neanderthal DNA in modern Asian, European, and American populations determined that on average around 2 percent of our genome evolved in a population of Neanderthals.
Since then a multitude of studies have found that tiny fraction carries big responsibilities. Not only do those genes potentially affect a handful of physiological traits we can see, but they also seem to have beefed up our immune system to handle more pathogens.
We've also found that percentage varies significantly around the world. Having Asian ancestry means you probably have 20 percent more Neanderthal DNA than if you descended from European stock, for example.
But those from an African background were thought to have missed out on the product of that ancient affair, with researchers previously failing to find any trace of the Neanderthal sequences in modern African populations.
Without knowing exactly what a full Neanderthal genome would look like, or how much of it is in our own bodies, researchers traditionally relied on statistical methods that compare various DNA sequences against a reference point. By assuming our modern genetic heritage flowed with a migrating human population, from west to east, ancestors who remained in Africa established a blank slate as far as Neanderthal genes went.
Using the results of those studies only verified those assumptions further.
With advances in Neanderthal DNA analysis in mind, Chen and her colleagues took a different approach based on what's known as identity by descent (IBD).
Rather than rely on assumed reference points to make comparisons, the team went straight to the Neanderthal's sequenced genome and applied the principle that close family relationships are more likely to have more genetic sequences in common.
You and your siblings will share, on average, about half of your DNA. That statistic drops by a predictable figure when you compare your genes with your grandparents'.
Go back half a million years to a time when Neanderthals and modern humans shared family members, and we can come up with a fraction of our DNA we might expect to share simply because we're related.
Applying this approach to 2,504 modern genomes from the 1000 Genomes Project, researchers found there are indeed stretches of DNA buried in African genomes that came from Neanderthals living on the Asian continent long after we all went our separate ways.
More precisely, about 0.3 percent of the average African's genome was once shared by a Neanderthal. All but a small fraction of that DNA can also be found in non-African populations, suggesting those genes weren't picked up during separate interbreeding events.
We can only imagine descendants of historic Neanderthal admixing returning west over the past 20,000 years, bringing their shiny new genes into Africa with them as they retraced their family's footsteps into the sunset. It's not just a neat idea; it's a scenario backed up by simulations based on the figures.
What's more, some of that Neanderthal DNA itself contained clear signs of genes inherited from recent human migrants, presenting researchers with hints of a complex game of genetic pass-the-parcel.
Pressing reset on an important reference point for determining our respective quantities of Neanderthal genetics means we need to rethink earlier conclusions.
Where previous research claims East Asians have 20 percent more Neanderthal DNA than Europeans, taking these new numbers into account means that figure could actually be as low as just 8 percent.
University of Washington population geneticist Kelley Harris wasn't involved in the study, but thinks the results should force other researchers to recalculate their numbers.
"We might have to go back and revisit a bunch of results from the published literature and evaluate whether the same technical issue has been throwing off our understanding of gene flow in other species," says Harris.
Adding more Neanderthal genomes to form a better reference library could improve the method's accuracy, while using the same approach with Denisovan genomes could also reveal a complex weave of human relationships through time and across the globe.
This research was published in Cell.
We were probably able to have babies more easily.
But what I do not understand is it seems scientists do not understand immigration is like a wave that goes back and forth.
So genes travel both ways.
Neanderthals were most likely taken out by roving bands of raping teens
DNA science is one that isn’t settled.
Every major new study creates new theories and often unsettles the previous DNA theories.
Also,politics and probably PCism is getting involved with the DNA science. That will probably screw up future DNA printouts
So, my African DNA was possibly polluted with Neanderthal DNA, and probably my snowflake Euro DNA. My snowflake Euro DNA, so far is mainly snowflake western Euro and the UK’s donations across those islands.
Every DNA linkage reports released by Ancestry have had a lot of changes.
The first big release 2 years ago, took away a lot of my Spanish and Iberian peninsula ancestors.
A big mystery to my siblings and cousins is the lack of Cherokee/any so called civilized tribal DNA in our reports. We have less than Fauxahontas. Yet we have written documentation re marriages, births and common law marriages showing over 150 documented so called Native Americans and zero DNA evidence.
Maybe Neanderthal females were hos..................
Especially in the area MORE important to Him and to us:
The African Neanderthal Bell Curve
I got book rights!
Africans then are one standard deviation short of a six pack.
Is that settled science?
Doubtful but picking a Cro-Magnon husband would have meant she had a greater possibility of having live babies and surviving the birth. For a Cro-Magnon man picking a Neanderthal would have had the same benefits. Children and a wife with better possibility of living.
So Neanderthal is the new ‘N’-word?!
The jokes just write themselves.
I don’t know, Neanderthals were at least as intelligent as us, they were shorter, stockier and very much stronger than we are. LOL
I guess that’s where the old saying comes from:
Men marry down. Women marry up......................
Ah crap! Does that means we all have that one, knuckle-dragging cave dweller in our family tree? LOL
Look around you at the table on the next holiday gathering or family reunion...................
In English it takes care of booze. Since the erstwhile "native american indians" had/have a deficiency in this enzyme we now know why they couldn't handle the white man's "fire water," alcohol.
All Oriental Asians have this deficiency,
Caucasian Asians: Indians, Pakistanis and Sri Lankans, have NO deficiency in this enzyme and can drink alcohol with no side effects.
They are also as HAIRY as Oriental Asians are NOT.
I do have a nephew who has to shave his eyelids. He is the hairiest person I have ever seen. He is a bat-guano crazy antifa type, but he’s family. What can you do?
I served in the Marines with a guy who was so hairy he looked like he was wearing a fur coat.................
the weird thing is that his brother has almost no body hair at all. same parents but a totally different batch of DNA apparently. Its weird.
Amen!
So if GEICO makes any new caveman commercials, they will have to have a black caveman or they are racist?
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