Artist's impression of a Neanderthal hunter. New evidence suggests the Neanderthals and modern humans interbred.
Credit: American Museum of Natural History
SYDNEY: Modern humans contain a little bit of Neanderthal, according to a new theory, because the two interbred and became one species.
The theory is the latest addition to the ongoing debate about what happened to this early species of human.
In a paper published this week in the U.S. journal Proceedings of the National Academy of Sciences, a team of European researchers report a "mosaic of modern human and archaic Neanderthal features" in 30,000 -year-old human fossils from Romania.
Co-author Erik Trinkaus from Washington University explains: "[Some] closely related species of mammals freely interbreed, produce fertile viable offspring, and blend populations." This is what appears to have happened with Neanderthals and modern humans, he says.
Shorter and stouter than modern humans, but with larger brains, Neanderthals lived in Europe, central Asia and the Middle East for about 170,000 years before disappearing between 33,000 to 24,000 years ago.
Their extinction coincided with the migration of modern humans out of Africa and across Europe. Few mysteries in the history of human ancestry have been as hotly debated as what caused the extinction of the Neanderthals.
Some scientific theories have Neanderthals dying out because they were less well-adapted to the climate changes that occurred across Europe at that time. Others cite evidence of a more brutal end, in which Neanderthals were slaughtered by modern humans.
This new study helps to settle the controversy. According to the researchers, the populations probably blended together through sexual reproduction. "Extinction through absorption is a common phenomenon," says Trinkaus.
The human remains were found in Pestera Muierii ('Cave of the Old Woman'), an elaborate cave system in Romania. First uncovered in 1952, the fossils remained poorly dated and largely ignored until recently.
Using carbon dating techniques, Trinkaus and colleagues found that the remains were 30,000 years old. Their analysis of the bones revealed diagnostic skeletal features of modern humans, including smaller eyebrow ridges, very narrow holes where the nostrils join the skull, and a shin bone that is flat on one side and concave on the other.
However the mostly human skeletons also possessed distinct Neanderthal features; features that were not present in ancestral modern humans in Africa. These include a large bulge at the back of the skull, a more prominent projection around the elbow joint, and a narrow socket at the shoulder joint.
Further analysis of one skeleton's shoulder showed that these humans did not have the full set of anatomical adaptations for throwing projectiles, such as spears, during hunting.
According to the researchers, this mixture of human and Neanderthal features suggests that a complicated reproductive scenario existed as humans and Neandertals interbred. The hypothesis that the Neanderthals were simply replaced should therefore be abandoned, they suggest.
Trinkaus says we may carry some of the genetic legacy of the Neanderthals within us. However it would be difficult to determine which of us are more closely related to the Neanderthals: "there has been 30,000 to 35,000 years of human evolution since then," he says.
Vikings & Neanderthals
One of my theories playing on the red hair signature is that the Vikings were pretty much known for this trait, in fact it was the Vikings that brought the English word "Freckles" into our language.
Just possibly the origin of the Vikings/Nordic's could be pre Cro-Magnon's either part of the wider Neanderthal group or a similar separate group that has likely exchanged DNA. (Any cross breeding over thousands of years will perculate out).
One thing that everyone seems to have missed? is that Ice Ages are on cycles of around 40-100k time frames. If Neanderthal split 500k years ago... wasn't there interchange with out of Africa peoples each time the ice retreated? or just maybe the interchange of DNA also worked its way back down into Africa every time there was an Ice age. Personally I see it almost like a potential tidal flow with those traits (esp attractiveness) being retained as important.
Another idea I have had (Although way out) regarding the connection with Neanderthal, is there any above average occurance of child birth problems when compared to the Animal kingdom?, Just seems that if Neanderthals were larger then it could have created problems with Child birth and maybe we still see that genetic wobble even now?
Neandertal and Modern Human admixture
I think that it is intellectually irresponsible to state in an article based only on Dr. Trinkhaus' research that the controversy regarding Neandertal and modern human interbreeding has been resolved. It absolutely has not. Many researchers in the field continue to believe that there was no admixture between the species. Consider last November's articles in both Nature and Science regarding the sequencing of nuclear DNA from Neandertals. Neither study, based on genetic rather than visual evidence, supports Dr. Trinkhaus' theory. In fact, the mitochondrial sequence for Neandertals, while admittedly focused at only one locus and inherited maternally, suggests exactly the opposite. Perhaps your reporter should do a bit more research before providing inaccurate information to teachers.
Damaged DNA etc
Personally I believe the burden of proof rests with those that believe there was no interchange.
Let’s apply some logic.
Neanderthal is supposed to be 500k years different the modern Cro Magnon. However, what actually happened in the various periodic Ice ages that occurred during that 500k year timeframe, as I discussed in a previous post?
If you believe Neanderthal was completely isolated for 500k years and didn't interbred with various outflows from Africa (or Asia) then it is equally plausible that Neanderthal from say Iraq (Germany etc) is 500k years different to Neanderthal in say France. Therefore different groups of Neanderthal are completely different by the same degree as the entrant (modern Cro Magnon man). Firstly prove they were a homogenous pool.
Ok, let’s say Neanderthal is completely different by 500k years and was somehow an isolated gene pool. So, Neanderthal cannot breed with Cro Magnon. Interesting, dogs that are 1,000k years different can interbreed.
Just perhaps they did interbreed and most Neanderthal DNA was inferior whether on a selective attribute or pure genetic, then most of it might have dissipated. Even a small genetic difference between European and say African may therefore be sufficient proof, For instance if African's have ZERO propensity to have red hair then just what does this prove about Europeans? Red hair offers no environmental attributes but could have some potential correlation to say heightened survival instinct (say intellectual aggression) for it to be such a prevalent genetic trait. So just where did this genetic coloring come from?
I think eventually we'll find that there were many variations of Neanderthal, some closer and some further away than modern man, and the closer elements have been subsumed into larger gene pools.
An interesting idea
To debate mDNA studies you would have to be stupid. However what if a hybrid could only be produced using a Male Neanderthal and a female Human. Two or three generations of this style interbreeding could more or less wipe out Neanderthal mDNA. Genius? maybe.
reverse that
You mean a male human with a female neanderthal. For a couple of reasons. First of all, it is much more likely that humans took neanderthals as concubines, and I don't think women took male neanderthal concubines. Also, it would have been easier for a neanderthal to give birth to a neanderthal baby than a human, I'm assuming. But, I don't think they did reproduce.
Burden of proof always lies
Burden of proof always lies on those making the positive proposition.
Just sayin'...
Mitochondrial DNA
Ok, You suggest that Mitochondrial DNA "only at one locus and inherited maternally" is different between Neanderthal and Cro Magnon.
Firstly, Maternal Mitochondrial DNA does NOT change as its passed always via the mother to offspring (And follows the daughters), Mitochondrial DNA is supposedly not present in the head of a sperm and as such is not subject to "admixture". So, any study of Mitochondrial DNA from Neanderthal should have a common root with modern man of 500,000 years ago. Also, I could propose that Neanderthals may not have been as "attractive" to the new entrants and as such the woman's mitochondrial DNA may have been washed away with genetic selection.
(Scientists need to look for potentially favourable dna elements and see whether they still exist).
One thing that seems not have been raised yet is the significant deepening of the haplogroup tree in Europe (relative to Africa etc). All the nodes of divergence seem to be contained well within the Neanderthal territory. Just what if these haplogroup changes were the outcome of Cro Magnon passing through "pools" of older tribes? If genetic change is a constant clock then why has it apparently ticked quicker in Europe?
Haplograph tree - rapid change in Northern Europe
Progressing on from the last statement it’s apparent that in the period 35-40k years ago rapid change occurred (M9 to M343) which is evident in Northern European Male (Y) haplogroup.
The progress of it say in a British Male is
M91>M168>M89>M9>M45>M207>M173>M343
Whereas a Southern European Male (Italy) is
M91>M168>M89>M304
Given the lineage of the British male is through the migration through Western Russia and then Northern Europe you can see the huge geographical distance covered. Whereas we see Italians having taken a "short cut" through Greece etc.
So what caused the Northern Europeans genetic clock to change quicker, I believe through interbreeding with less similar tribes as the migration occurred, basically creating greater variability on DNA replication (Including impacts on the Y element).
Characteristics
This would certainly explain my barrell chest and back hair. Don't have the protruding brow though....probably lost in translation.
Neanderthals breeding with humans
Even if the skeletons are neanderthal-sapiens hybrids, one group interbreeding in one area did not necessarily have anything to do with groups elsewhere, nor does some interbreeding mean a peaceful end to Neanderthal-- Europeans interbred with Native Americans even as they were destroying them, not by reproductive absorption, but by disease, war, and habitat displacement.