Posted on 03/20/2012 4:55:36 AM PDT by Renfield
The complex world of human genetics research speaks a language unfamiliar to most of us, but it has opened up a new window on our understanding of the dynamics of ancient populations; and few areas of research have been more tantalizing than that surrounding the questions of how modern humans are related to the Neandertals, an ancient species of human whose morphology or physical characteristics disappeared from the human fossil record roughly 30,000 years ago. The most recent studies have provided evidence about when the Neandertal (Homo neandertalensis) and modern human populations (Homo sapiens) first diverged from a common ancestral population. They have also suggested that Neandertals and ancient modern humans interbred, and that some distinct modern populations have more Neandertal ancestry than others.
In a 2010 benchmark study conducted by a consortium of scientists and institutions, researchers compared and analyzed a Neandertal genome constructed from samples taken from the bones of three Neandertal individuals excavated at the Vindija Cave in Croatia. A genome is an organism's complete hereditary information as encoded encoded in DNA. They compared the genome with modern human genomes from a sampling of present-day human groups from different parts of the world. What they found was a number of genetic variants in regions along the genome that both Neandertals and modern humans shared as a result of positive natural selection, "including genes involved in metabolism and in cognitive and skeletal development". [1]
The evidence suggested some additional conclusions. One of them deals with the long-standing debate about when modern humans and Neandertals diverged in the time-line of evolution. Examination of the new data now indicates that the split took place between 270,000 and 440,000 years ago, "a date that is compatible with some interpretations of the paleontological and archaeological record" and a common ancestor that lived within the last 500,000 years. [1]
Equally significant is the answer they found regarding how the Neandertal genome variants ended up in the modern human genome in the first place.
"A challenge in detecting signals of gene flow between Neandertals and modern human ancestors," state the study authors in the report, "is that the two groups share common ancestors within the last 500,000 years, which is no deeper than the nuclear DNA sequence variation within present-day humans. Thus, even if no gene flow occurred, in many segments of the genome, Neandertals are expected to be more closely related to some present-day humans than they are to each other. However, if Neandertals are, on average across many independent regions of the genome, more closely related to present-day humans in certain parts of the world than in others, this would strongly suggest that Neandertals exchanged parts of their genome with the ancestors of these groups." [1]
In other words, if there are differences in the degree to which different geographically dispersed present-day population groups show Neandertal ancestry, this would suggest that Neandertals and ancient modern human ancestors interbred.
*We performed this test using eight present-day humans: two European Americans (CEU), two East Asians (ASN), and four West Africans (YRI) We find that the Neandertals are equally close to Europeans and East Asians....... However, the Neandertals are significantly closer to non-Africans than to Africans." [1]
The researchers' best explanation for these findings is that the Neandertals exchanged genes with the ancestors of non-Africans. Eurasian Neandertals interbred with ancient modern humans. But, the study authors continue, "the actual amount of interbreeding between Neandertals and modern humans may have been very limited, given that it contributed only 1 to 4% of the genome of present-day non-Africans". [1]
What is more, they were able to determine the relative time in which the mixing began:
A striking observation is that Neandertals are as closely related to a Chinese and Papuan individual as to a French individual, even though morphologically recognizable Neandertals exist only in the fossil record of Europe and western Asia. Thus, the gene flow between Neandertals and modern humans that we detect most likely occurred before the divergence of Europeans, East Asians, and Papuans. This may be explained by mixing of early modern humans ancestral to present-day non-Africans with Neandertals in the Middle East before their expansion into Eurasia. Such a scenario is compatible with the archaeological record, which shows that modern humans appeared in the Middle East before 100,000 years ago whereas the Neandertals existed in the same region after this time, probably until 50,000 years ago. [1]
Any canoodling, then, may have actually started before the two species encountered each other in what is now present-day Europe or West Asia.
The picture becomes more complicated with later studies, which have shown some interesting new details. John Hawks, Associate Professor of Anthropology at the University of Wisconsin—Madison, reports the results of a study of the comparison of East Asian region samples (Japanese, Han Chinese in Beijing, and Han Chinese originating in South China) with European region samples (Tuscans, British, Finn, CEU, and Spanish) taken from the 1000 Genomes Project in his weblog entitled The Malapa Soft Tissue Project. Here he concludes that "the Europeans average a bit more Neandertal than Asians", suggesting that "Europeans may have mixed with Neandertals as they moved into Europe, constituting a second process of population mixture beyond that shared by European and Asian ancestors". [2] More interesting still were the differences detected among the samples within each of the two regions. Within the East Asian region, the North China population was found to have more Neandertal indicators than the South China, and within the European region, the southern populations more than the northern, with the Tuscans having "the highest level of Neandertal similarity of any of the 1000 Genomes Project samples". [2] Hawks relates the results of research on African populations, as well, which also show variability. He points to the Yoruba people, a West African population, having significantly more Neandertal genome similarity than the Luhya, an East African population. "We now know from examination of genetic variation within Africa today," states Hawks about the possible implications, "that some of today's diversity can be traced to ancient population structure in Middle Pleistocene African populations. For example, Neandertals could be more closely related to some African populations than others today because Neandertals actually exchanged genes with some ancient African populations. Or Neandertals might have sprung from one African population among many who lived 250,000 years ago..........As we combine the archaic genome data with our growing picture of diverse lineages in Africa today, we may discover ancient populations that are not apparent archaeologically. Again, genetics is giving us a totally new picture of the diversity and population dynamics of ancient people." [2]
Genome research continues to provide new findings through an expanding source of shared data, affording new details. Looking forward, Hawks asks the next question: "Which Neandertal-derived variants are shared between regions, and which are unique to one region?......Now, we have sequences capable of telling us much more." [2]
[1] Green, Richard E., et.al., A Draft Sequence of the Neandertal Genome, Science 7 May 2010, Vol. 328 no. 5979 pp. 710-722 DOI: 10.1126/science.1188021.
[2] John Hawks, The Malapa Soft Tissue Project, Weblog at http://johnhawks.net/malapa.
In the battle for genetic survival, who's smarter: the 43% that sponge & breed like rats; or the 57% who feed, clothe, and house the 43% by working themselves to such an extent that they breed at less than replacement levels?
In any case, interesting article...and comments.
Truth is, though, they are ALL wrong...even the classification!
It should really be Homo Habitual-Cuss -> H. Erect-Cuss -> H. Meandering-Cuss -> H. Magnum-Cuss -> H. Modern-Cuss -> H. Domestic-Cuss, with a co-lateral wild population side-branch, H. Rotten-Cuss.
Naturally, there are a few dead end & extinct offshoots & side branches here & there, but that is the basic phylogeny.
Oh, and H. Domestic-Cuss is currently dividing into separate strains: H. D ssp Effeticuss & H.D. ssp Robusticuss...AKA Liberals & Conservatives.
Yes I know that.
It may very well turn out that there has been genetic input into modern Humans from the Neanderthals, but this research doesnt prove it.
Once again, for any newcomers or anybody who might have missed it, this is what Neanderthals looked like (with the 8" fur coat removed):
With the fur coat:
Images courtesy of www.themandus.org
The 8" fur coat is why nobody's ever found a Neanderthal needle, a creature with an 8" fur coat doesn't NEED clothing or needles. SunnkenCiv and one or two other Neanderthal-Apologists on FR are basically perpetrating a fraud at this point.
If that thing in your pictures is what Neanderthals really looked like, then that thing wasn’t making pressure flaked stone blades and fashioning them to spears and such. No way in God’s green earth. That thing is quite a few evolutionary steps short of a tool making animal.
Neanderthals were cannibals who buried their own dead, which is sort of a conundrum if you think about it. They find Neanderthal bones with cut marks from butchering and no indication of Cro Magnons having eaten them or been around. What it suggests is that, like chimpanzees or mammalian predators, they never had any sort of organization beyond the family group level and probably viewed the living world as two separate categories i.e. their own family group, and meat.
Other than that.... they did have fire (which they had to be terribly careful of with the 8” fur coats), and they did have stone tools. Other hominids appear to have had stone tools as well.
I remember that when I first started reading about this on FR that the DNA was showing that modern humans and Neaderthals couldn’t interbreed. The ‘boners; held out that they could.
Wonder what the next twist will be?
OK, I may be dense. My wife says so anyway. But I fail to see the relevance of the verse to the subject???
I don’t know. Men in modernish times have been known to mate with walruses, goats, chicken, horses, and each other.
How ugly can the girls be compared to that? Excepting Helen Thomas, of course.
Interesting. Did he actually get fetuses, viable or not? Do you have a specific link that you are relying on, rather than me googling up a thousand? Thanks.
I believe they were talking about mitochondrial DNA, and found no evidence of interbreeding, Studies of other parts of the DNA show substantial evidence of interbreeding. I think mitochondrial has some unique properties with respect to ancestry that should be considered when analyzing ancestral interbreeding.
..........
I think that means the neanderthal males bred with the homo sapien females since the mitochondrial DNA is passed through the females. (I may have this backwards.)
You’re saying the females of neanderthal species would be too repugnant for the male of the homo sapien species.
I’ll buy that.
However, since the data shows that the mitochondria didn’t change—what that means is that it was male neanderthal that interbred with homo sapien females.
They also place the interbreeding +-125,000 years ago in the middle east
That’s entirely possible. All that would take would be one battle between homo sapiens and neanderthals in which the neanderthals won and killed the homo sapien males. In the middle east the neanderthals coexisted with the homo sapiens according to the data up until 50,000 years ago. That puts them in the same area as homo sapiens for at least 75000 years. That leaves plenty of time for a neanderthal male to get lucky.
... If no Neanderthal mitochondrial DNA is found, that indicates that any inter-racial mating involved Neanderthal men mating CroMag women... 37 posted by PapaBear3625
Yes. It seems the Cro Mag ladies returned to their Cro Mag families after the (perhaps involuntary) experience, and if any vice versa matings occurred, the Neanderthal ladies did not join Cro Mag.
There are two reasons for rejecting that, either of which alone would suffice.
Having that happen 125K years ago would be well prior to the recent bottleneck; all humans would have the Neanderthal genes, and not just Asians and Caucasians.
Two, what that would have to involve, would be some Neanderthal male kidnapping and raping a human woman and then, rather than cooking and eating her (as usual)keeping her alive long enough to bear a cross-species child and then somehow raising that freak child to be old enough to breed back into human populations and somehow trick the humans into not immediately killing all of the crossspecies freaks and freaklets involved in all of that.
In real life of course, the original woman would either be cooked and eaten when the Neanderthal male was finished with her or killed by the Neanderthal females the first time her new owner left her alone for fifteen secondes...
Use your head, this **** is an evolutionite fairytale.
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