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Modern Humans With African Ancestry Have More Neanderthal Genes Than We Thought
www.sciencealert.com ^ | 31 JAN 2020 | MIKE MCRAE

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.


TOPICS: History; Music/Entertainment; Society; Sports
KEYWORDS: godsgravesglyphs; helixmakemineadouble; neandertal; neandertals; neanderthal; neanderthals
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To: txnativegop

“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.”

One of our adult sons has minimal body hair, light and sparse beard and gets his military haircut every months.

His sibling is like me. Hair all over.

Genetics can be funny/odd.


41 posted on 01/31/2020 3:32:07 PM PST by Grampa Dave (So called Cures for most viruses are imaginary. ItÂ’s always been best, ride it out, survive or die.)
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To: Red Badger

So let me get this straight. At some point in the past neanderthals and Cro-Magnons mated and produced offspring that could in turn be fertile and produce offspring themselves. This has to be case since many if not most modern humans have neanderthal DNA.

Doesn’t that make neanderthals and Cro-Magnons the same species then? How can science classify them as separate species?


42 posted on 01/31/2020 4:00:53 PM PST by JoeRender
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To: JoeRender

Species designation is vague and fraught with guesses, errors, etc. Species are defined not only by reproductive fidelity and success (which we don’t always know), but also geographically and through time.

This is one example of many instances of the impreciseness of science.


43 posted on 01/31/2020 4:12:29 PM PST by LaRueLaDue
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To: Red Badger
in 3.....2.....1.....
44 posted on 01/31/2020 4:14:00 PM PST by Viking2002 (Epstein and Ukraine Airlines Flight PS752 didn't kill themselves. Yeah, I went there.)
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The Neandertal Enigma
by James Shreeve

in local libraries
"Frayer's own reading of the record reveals a number of overlooked traits that clearly and specifically link the Neandertals to the Cro-Magnons. One such trait is the shape of the opening of the nerve canal in the lower jaw, a spot where dentists often give a pain-blocking injection. In many Neandertal, the upper portion of the opening is covered by a broad bony ridge, a curious feature also carried by a significant number of Cro-Magnons. But none of the alleged 'ancestors of us all' fossils from Africa have it, and it is extremely rare in modern people outside Europe." [pp 126-127]

45 posted on 01/31/2020 11:16:08 PM PST by SunkenCiv (Imagine an imaginary menagerie manager imagining managing an imaginary menagerie.)
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To: 240B; 75thOVI; Adder; albertp; asgardshill; At the Window; bitt; blu; BradyLS; cajungirl; ...
Thanks fieldmarshaldj. So, I guess Red Badger had seen this one before my FReepmail...
Here are the other GGG topics introduced since the previous Digest ping:

46 posted on 01/31/2020 11:16:30 PM PST by SunkenCiv (Imagine an imaginary menagerie manager imagining managing an imaginary menagerie.)
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To: JoeRender
Because of longstanding master-race biases.

47 posted on 01/31/2020 11:17:32 PM PST by SunkenCiv (Imagine an imaginary menagerie manager imagining managing an imaginary menagerie.)
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To: Red Badger

Once again, sampling and statistical assumptions turn out to be in error.
So one assumes that the Neanderthals heard about the hot African chicks and wandered back to see whats up?

Is there any Denisovian in African DNA?


48 posted on 02/01/2020 3:07:22 AM PST by Adder (Mr. Franklin: We are trying to get the Republic back!)
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To: LaRueLaDue

Understood. But it is a pretty firm rule that if two animals can produce offspring that can in turn reproduce then they are the same species. It would seem to me that the Neanderthals were simply a race of humans and not an actual species.

It’s almost as if there is a scientific orthodoxy that tries to define the Neanderthals as a species rather than a race because it seems to fit a certain narrative.


49 posted on 02/01/2020 8:49:12 AM PST by JoeRender
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To: Red Badger
"I'm not a high-brow. I'm not a low-brow. I'm something new. I'm a no-brow"

- Joe E. Ross.


50 posted on 02/01/2020 8:59:00 AM PST by P.O.E. (Pray for America)
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To: SunkenCiv

I told you....we’re all Neanderthals.


51 posted on 02/01/2020 9:13:40 AM PST by blam
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To: blam
Among other things!

52 posted on 02/01/2020 11:30:38 AM PST by SunkenCiv (Imagine an imaginary menagerie manager imagining managing an imaginary menagerie.)
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To: Red Badger

My college dorm had a guy who was 6’6” tall, had long scraggly dark red hair and beard, and an enormous amount of dark red body hair. We all called him “Yeti”.


53 posted on 02/01/2020 12:31:38 PM PST by Thud
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To: Adder

Eddie Griffin, To beautiful Bi-racial girl: You got any black in you?

Girl: Yes.

Eddie: You want some more?..................


54 posted on 02/03/2020 6:43:21 AM PST by Red Badger (Against stupidity the gods themselves contend in vain.......... ..)
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To: Grampa Dave

It’s entirely possible to have no genetic heritage from an ancestor as recent as a great grandparent, let alone a Cherokee spouse or two back in the Appalachian frontier era. Far more of the legendary claims of Cherokee ancestry may have basis in fact than is currently believed, but there is no way to prove that via genetic testing currently.


55 posted on 02/03/2020 6:51:13 AM PST by RegulatorCountry
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Roasting would have been easy. But re-creating the paleo way of boiling water requires a bit more imagination. On a blustery day in October, Andrew Langley and 13 other graduate students headed to the woods to learn to boil water. They were allowed no obvious cooking vessels: no pots, no pans, no bowls, no cups, no containers at all. But they did bring deer hides, which Langley had carefully procured from deer farms. They were to boil water the Paleolithic way. Langley is a doctoral student in archaeology at the University of York, and he studies how prehistoric humans cooked without pottery. Ceramics are a relatively recent invention in the long arc of human history. Pottery shards appear in the archaeological record only 20,000 years ago, first in China and then many millennia later in the Near East and Europe...

56 posted on 02/04/2020 11:13:57 AM PST by SunkenCiv (Imagine an imaginary menagerie manager imagining managing an imaginary menagerie.)
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