But isn’t that evidence pretty scarce, and only after possible contact with Modern Humans? I could be wrong, but I didn’t think we had evidence for widespread use of jewelry before possible contact with Moderns.
Thinking about the 1-4% DNA from Neanderthals, I think what that means is that non-Africans trace 1-4% of their ancestry to Neanderthals. And given that those Neanderthals shared 99.5% of their DNA with us, that’s only a tiny contribution of DNA that actually differed from ours.
Two points:
First, the “lumping of (sub-saharan) Africans” is a ridiculously broad lumping of diverse populations into a “race.” The thing that is sensitive, and makes them lumpable at all biologically is the category of “those who do not share a Neanderthal heritage.” Historically, in my view, modern anthropologists have discouraged biologic race categorizations on the general notion that we are all subset diverse populations branching off the same monogenetic trunk. Since Neanderthals are different in some more profound way, and since (broadly speaking) there are such disparities in outcomes between the (putative) categories of some-Neanderthal and no-Neanderthal in the modern world, I expect fairly rigorous examination of Paabo’s paper, and should it turn out to hold up, fairly rigorous debate on the function and significance of any Neanderthal genes. The implication of the paper is that there are two trunks–some-Neanderthal and no-Neanderthal–and the authors use the term “cognition” regarding some of the genes studied, both in the abstract and the summary. I was surprised they called that out.
Second point is a nitpick. I may be reading the paper incorrectly, but I think one of the suggestions in it is that the mixing may have occurred in a first out-of-Africa group, perhaps on the order of 100,000 or more years ago. I am not sure about this point, and I may have misconstrued it as I have not really digested the contents yet.
You are correct. Current research is not suggesting that modern humans who may have some Neandertal genetic heritage are more different from other modern humans than from chimpanzees.
As the Science article notes, humans and Neandertals had common ancestors within the past 500,000 years, whereas humans and chimps diverged from a common ancestor over 4 million years ago. So our human ancestors already shared much more DNA with Neandertals than with chimpanzees even before some northern subgroup(s) of them allegedly started getting it on with their Neandertal cousins in those dimly lit caves.
Saying that we share 98.5% (or 96%, depending on how you count) of our DNA with chimps is a way of saying that the human genome and the chimp genome are very similar. Saying that we get 1%-4% of our genes from Neandertals, or that you share 100% of your DNA with your identical twin brother but only 50% with your father, is a way of describing individual differences within the human genome. Clearly, you are not more closely related to a chimpanzee than to your father.
We don’t really know how “profound” the difference was between Neanderthals and Modern Humans.
The data suggest two periods of mixing-- one at about 60k years ago and one at about 45k years ago.
I’m not sure how you got from “however rare” to “significant”, but significant the breeding between Neanderthal and Modern Man was not. I’m not sure if you’re driving towards an overly-literal definition of species, but be aware that horses (64 chromosomes) have produced fertile offspring with both donkeys (62) and 66-chromosome equids.
Whatever the genetic similarity between hominids, social differences may have meant that some cross-mating arose only in ravage-and-ravish scenarios.
Another post suggests you believe the recency of mtDNA-Eve and Y-dna Adam in Africa is incompatible with a multi-region hypothesis. This is not the case.
They are proposing several scenarios for human-Neandertal genetic relationship, which are not mutually exclusive. What they call the most “parsimonious” explanation is the hypothesis that, as you say, Neandertals interbred with ancestors of all non-African humans shortly after the departure from Africa, which is why Neandertals seem to be equally similar to non-Africans from New Guinea, France, and China.
Other scenarios involve (1) hypothesized late Neandertal interbreeding with humans in Europe and/or western Asia alone (which wouldn’t explain the Neandertal resemblance in, say, Chinese humans), and (2) the hypothesis that the ancestors of modern non-Africans were simply more closely related to Neandertals than other humans were (the “ancient substructure” idea), way back before they left Africa.
I think you may be slightly misunderstanding what they’re saying. They aren’t claiming that the hypothesized “some-Neandertal” modern humans have genetically different cognitive abilities from the “no-Neandertal” modern humans. Rather, they’re offering evidence that modern humans as a whole have genetically different cognitive abilities from Neandertals.
In other words, they were using these human/Neandertal genetic comparisons to screen for genetic differences between Neandertals and ALL humans, as well as to detect genetic similarities between Neandertals and certain humans due to hypothesized post-divergence interbreeding.
What they found is that early modern humans since their divergence from Neandertals evolved certain human-specific characteristics due to positive selection that made them different from Neandertals. Some of those characteristics included changes in skull shape and cognitive abilities.
What this is saying is simply that early humans evolved by positive selection to have some differences in cognitive abilities from their Neandertal cousins, an idea that we’re already familiar with in a crude form as the classic “smart Homo sapiens versus dumb caveman” stereotype.
There is nothing un-PC or socially controversial about that idea, so there’s nothing surprising about the study’s authors “calling it out”.
So? Who said that the mating had to be voluntary? It just had to have been … and produce progeny.
No, I’m just pointing out that the way we define the term “species” makes inter-species breeding rare, not the other way around.
I’m referring to the Biological Species Concept, which is a precise, scientific term. Whatever happens between horses and donkeys in captivity is irrelevant to that definition as it describes populations in the wild only.
Possibly, but that is pure speculation.
I have no idea what you’re talking about here. I never posted about Adam or Eve in this thread.
Where did Neanderthal evolve? I thought all humans came out of Africa.
All humans did come out of Africa. Neandertals were hominids of the genus Homo, but not humans in the sense of belonging to the species Homo sapiens.
Neandertals, like all Homo species, are descended from an African hominid ancestor, but their remains have been found only in Europe and West Asia, AFAIK. They seem to have evolved into the separate Neandertal species outside of Africa, unlike our modern human ancestors who had become Homo sapiens before migrating out of Africa.
Good question, and highlights the necessity of defining what “human” is. Note that many of us, me included, are careful to say "modern humans’ when we’re talking about H. sapiens. “Human” can mean anything from H. sapiens, to any human ancestor since our split with the chimp line. Or, it might mean any member of the genus Homo.
Our line split from the chimp line, in Africa, about 6M years ago. Since then, there were several migrations out of Africa starting about 2M years ago. Neanderthals appear to have evolved in Europe from a population that left maybe 500k years ago.
Meanwhile, of those populations that remained in Africa, one evolved into us-- Modern Humans or H. sapiens. We didn’t leave Africa until about 60k years ago, but it appears that when we met our Neanderthal cousins in the Middle East and/or Europe, we hooked up and produced some fertile hybrids.
Thanks!
I’d recommend reading some of the discussion on GNXP where some of the relevant academics discuss the findings. Also, see John Hawks post on it.
Interestingly, that blog quotes Wolpoff:
Hah! His hypothesis (not a theory) was that Neanderthals evolved into Europeans, not that they added some tiny amount of DNA to an African population that evolved into Europeans. The Out of Africa hypothesis wasn’t absolutist about there being no admixture-- just that if there was any, it was small and difficult to detect. Not to mention that he argued for evolution of H. erectus populations into modern humans in Asia.
Wolpoff argued for small amounts of gene flow between relatively geographically stable populations, which is not what this new data is saying happened.
I’ll be interested to see if this gets clarified. The article is not about cognitive abilities of Neandertal versus modern humans, so I assumed the discussion on page 717 is referring to positive selection of genes made available by mixing with Neandertals. However I’ve read through it a couple times and admit I’m still not confident this is correct.
In general, the distribution of other genes putatively involved in cognition (microcephalin, e.g.) showing disproportionate distribution between Africans and non-Africans for haplogroup D fits into a similar scenario set to Figure 6 on p 721 of the current Science article. The “most parsimonious” scenario #3 creates two trunks at the point of Neandertal mixing. Although the diagram does not show them as two trunks, essentially you have one trunk for non-Africans and the other for Africans at the right point of the arrow for scenario 3.
I think what’s socially controversial–or potentially so–is the general notion that only modern non-Africans had access to Neandertal gene pools. If mixing did occur, any advantageous genes would appear only in the non-African trunk.
I’m not sure if you are talking about homo sapiens or Neanderthals.
Neanderthals were making beads out of shells 50,000 years ago. And the wild thing is that they have some sort of glitter on them. There is speculation that they may have used glitter makeup too! They sometimes used pigments on their faces and bodies, but they were not elaborate at all. These shell-beads were found in Southern Spain.
Neat hair? Hair styles come and go. Combs might not have been a high priority on the tool list. I really stunned at how far they had developed!
There is evidence that homo sapiens had shell beads in more than one location (South Africa, Israel, Algeria) about 100,000 years ago.
This passion for jewelry is in our genes, guys. It’s primitive.
nm.
Like aruvqan, it is really starting to bug me that in all of these Neanderthal reconstructions, the hair is so unkempt.
All apes love to groom one another. It is a highly social thing, with the added advantage of parasites being picked out and the fact that well groomed fur insulates better. Besides these people had lots of time to groom each other and themselves. They had no Tv, after all.
And when you don’t have much stuff and even a necklace takes so much trouble to make, grooming your appearance is a very natural way of improving your status and expressing your ties to a certain social group (your family, your tribe, your totem animal, or whatever).
Modern “primitive” tribes often have very elaborate hairstyles, and they do so with nothing more then a twig or maybe a primitive comb, a flint knife to shave parts of the head, a little piece of rope bark to tie a pony tail or a braid, and maybe some mud, fat, ashes for hair gel. Add flowers, fur, pieces of bone or feathers for embellishment, and things can get quite elaborate.
