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Originally Posted by Dragonsblood1987
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actually its believed that they reproduced so frequently, that neanderthals were essentially bred out of existence. they were genetically different, yes, but their brain size, intelligence, behavior (like hunting, burying their dead, making tools ect), were very similar. keep in mind that when it comes to genetics, even a fraction of a percent is a substantial difference. we're something like 96% genetically identical to chips.
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Believed by you? Common myth? The Wikipedia page? I just skimmed over several research papers in quality journals (including the one I cited, "This discontinuity is difficult to reconcile with the hypothesis that both Neandertals and early anatomically modern humans contributed to the current European gene pool") claiming the contrary. One of them claimed something like less than 200 occurrences estimated. I'm not an expert in the field or whatever, but it seems far from some settled fact. That's not to say that others don't have other opinions (that maybe there was more interbreeding) but the 'interbreeding to extinction' hypothesis never shows up in anything recent. But note that MOST studies that come up in any respectable publication estimate a fairly low successful interbreeding rate between the two species.
The article I cited is from PNAS, a rather respectable academic journal. Here's another from PLoS Biology, again very respectable.
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Originally Posted by Currat et al. 2004, PLoS Biology
The process by which the Neanderthals were replaced by modern humans between 42,000 and 30,000 before present is still intriguing. Although no Neanderthal mitochondrial DNA (mtDNA) lineage is found to date among several thousands of Europeans and in seven early modern Europeans, interbreeding rates as high as 25% could not be excluded between the two subspecies. In this study, we introduce a realistic model of the range expansion of early modern humans into Europe, and of their competition and potential admixture with local Neanderthals. Under this scenario, which explicitly models the dynamics of Neanderthals' replacement, we estimate that maximum interbreeding rates between the two populations should have been smaller than 0.1%. We indeed show that the absence of Neanderthal mtDNA sequences in Europe is compatible with at most 120 admixture events between the two populations despite a likely cohabitation time of more than 12,000 y. This extremely low number strongly suggests an almost complete sterility between Neanderthal females and modern human males, implying that the two populations were probably distinct biological species.
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And another by the same author in PNAS
[QUOTE-Currat et al. 2011, PNAS]Recent studies have revealed that 2–3% of the genome of non-Africans might come from Neanderthals, suggesting a more complex scenario of modern human evolution than previously anticipated. In this paper, we use a model of admixture during a spatial expansion to study the hybridization of Neanderthals with modern humans during their spread out of Africa.
We find that observed low levels of Neanderthal ancestry in Eurasians are compatible with a very low rate of interbreeding (<2%), potentially attributable to a very strong avoidance of interspecific matings, a low fitness of hybrids, or both. These results suggesting the presence of very effective barriers to gene flow between the two species are robust to uncertainties about the exact demography of the Paleolithic populations, and they are also found to be compatible with the observed lack of mtDNA introgression. Our model additionally suggests that similarly low levels of introgression in Europe and Asia may result from distinct admixture events having occurred beyond the Middle East, after the split of Europeans and Asians. This hypothesis could be tested because it predicts that different components of Neanderthal ancestry should be present in Europeans and in Asians.[/QUOTE]
07-09-2014, 02:49 PM
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