Originally posted by: Vee
Originally posted by: interchange
Some scientists believe that Neanderthal man was actually assimilated into our species instead of just being wiped out.
I'm afraid these are old speculations. We now know, for sure, that there was no assimilation whatsoever. The evidence is in DNA, and IIRC, mitochondry DNA.
Either mating couldn't produce any offspring, or any fertile offspring, or the idea was simply completely repulsive to both species.
I'm sorry, but you're espousing old speculations. Very few paleoanthropologists take the extreme position that Neandertals never interbred with the ancestors of modern humans. Not many molecular anthropologists do, for that matter. I personally find the evidence for some admixture more compelling. We do not know for sure either way. The fate of the Neandertals is still an enigma.
Originally posted by: Vee
There have been more than one study I think.
Sure, here are 20 more:
1. Cann, R. (1987) Mitochondrial DNA and human evolution. Nature. (325) 31-36.
2. Eller, E. (2001) Population extinction and recolonization in human demographic history. Mathematical Biosciences. (177 & 178) 1-10.
3. Excoffier, L. (2002) Reconstructing the demography of prehistoric human populations from molecular data. Evolutionary Anthropology Suppl. (1) 166-170.
4. Foley, R. (1998) The context of human genetic evolution. Genome Research. (8) 339-347.
5. Hammer, M. et al. (1998) Out of Africa and back again: nested cladistic analysis of human Y chromosome variation. Mol. Biol. Evol. 15 (4) 427-441.
6. Hammer, M. et al. (2001) Hierarchical patterns of global human Y chromosome diversity. Mol. Biol. Evol. 18 (7) 1189-1203.
7. Harding, R. et al. (1997) Archaic African and Asian lineages in the genetic ancestry of modern humans. Am. J. Hum. Genet. (60) 772-789.
8. Harpending, H. et al. (1998) Genetic traces of ancient demography. PNAS. (95) 1961-1967.
9. Harpending, H. & Rogers, A. (2000) Genetic perspectives on human origins and differentiation. Annu. Rev. Genomics Hum. Genet. (1) 361-385.
10. Hawks, J. et al. (2000) Population bottlenecks and Pleistocene human evolution. Mol. Biol. Evol. 17 (1) 2-22.
11. Hey, J. (1997) Mitochondrial and nuclear genes present conflicting portraits of human origins. Mol. Biol. Evol. 14 (2) 166-172.
12. Hurles, M. & Jobling, M. (2001) Haploid chromosomes in molecular ecology: lessons from the human Y. Molecular Ecology. (10) 1599-1613.
13. Kaesmann, H. & Pääbo, S. (2002) The genetical history of humans and the great apes. Journal of Internal Medicine. (251) 1-18.
14. Ovchinnikov, et al. (2000) Molecular analysis of Neanderthal DNA from the northern Caucasus. Nature. (404) 490-493.
15. Penny, D. et al. (1995) Improved analyses of human mtDNA sequences support a recent African origin for Homo sapiens. Mol. Biol. Evol. 12 (5) 863-882.
16. Przeworski, M. (2000) Adjusting the focus on human variation. Trends in Genetics. 16 (7) 296-302.
17. Relethford, J. & Jorde, L. (1999) Genetic evidence for larger African population size during recent human evolution. Amer. Jour. Phys. Anth. (108) 251-260.
18. Rogers, A. (2001) Order emerging from chaos in human evolutionary genetics. PNAS. 98 (3) 779-780.
19. Seielstad, M. et al. (1999) A view of modern human origins from Y chromosome microsatellite variation. Genome Research. (9) 558-567.
20. Vigilant, L. et al. (1991) African populations and the evolution of human mitochondrial DNA. Science. (253) 1503-1507.
John Hawks at Wisconsin-Madison has a blog in which he often discusses the genetics of human evolution. It's at johnhawks.net.
The basics of so-called Neandertal genetic incompatibility are: only relatively short sequences of mitochondrial DNA have been extracted from Neandertals. They have been shown to be different from modern sequences when analyzed as a population, but individually they are within the range of observed modern human sequences. Mitochondrial DNA has a host of other issues that cast doubt on its ability to reconstruct ancient demographic patterns, anyway.
If (and that's a big if) a Neandertal nuclear sequence were recovered, how would we know it was, in fact, Neandertal, and not modern contamination? (Believe me, it takes a lot of work to get bones from the field to the lab, specimens pass through a lot of hands.)
In short, there is scant evidence that Neandertals were genetically incompatible (a different species) with modern humans, or their 'more modern looking' contemporaries.