Néandertal incompatible avec l’homme moderne
[b]Oui, effectivement, je profite du titre du sujet pour parler de réalité et non pas de délires hypothétiques
de cette publication précitée :[/b]
Essayez de traduire et de comprendre les gars comparent même avec le Chimpanzé actuel qui ferait partie de nos origines.
We have estimated that the Neandertal Y chromosome from El Sidrón diverged from those of modern humans ∼590 kya, a value similar to TMRCA estimates for mtDNA sequences: 400 kya to 800 kya.11
This time estimate and the genealogy we have inferred strongly support the notion that the most recent common ancestor of these Y chromosomes belonged to the population from which Neandertals and modern humans diverged, thereby refuting three alternative hypotheses. A priori, the Neandertal Y could have introgressed from a super-archaic population5
(Figure 3, scenario a), but this would have led to a far greater TMRCA estimate. Alternatively, it could have introgressed from the ancestors of modern humans after their divergence from Neandertals and prior to the most recent common ancestor of present-day Y chromosomes (scenario b) or from modern human populations subsequent to their migrations out of Africa (scenario c). We can also reject these hypotheses, as each requires a more recent split time.
Thumbnail image of Figure 3. Opens large image
The fact that the Neandertal Y-chromosome lineage we describe has never been observed in modern humans suggests that the lineage is most likely extinct. Although the Neandertal Y chromosome (and mtDNA) might have simply drifted out of the modern human gene pool,24
it is also possible that genetic incompatibilities contributed to their loss. In comparing the Neandertal lineage to those of modern humans, we identified four coding differences with predicted functional impacts, three missense and one nonsense (Table 1). Three mutations—within PCDH11Y, USP9Y, and TMSB4Y—are unique to the Neandertal lineage, and one, within KMD5D, is fixed in modern human sequences. The first gene, PCDH11Y, resides in the X-transposed region of the Y chromosome. Together with its X-chromosome homolog PCDH11X, it might play a role in brain lateralization and language development.25
The second gene, USP9Y, has been linked to ubiquitin-specific protease activity26
and might influence spermatogenesis.27
Expression of the third gene, TMSB4Y, might reduce cell proliferation in tumor cells, suggesting tumor suppressor function.28
Finally, the fourth gene, KDM5D, encodes a lysine-specific demethylase whose activity suppresses the invasiveness of some cancers.29
Polypeptides from several Y-chromosome genes act as male-specific minor histocompatibility (H-Y) antigens that can elicit a maternal immune response during gestation. Such effects could be important drivers of secondary recurrent miscarriages30
and might play a role in the fraternal birth order effect of male sexual orientation.31
Interestingly, all three genes with potentially functional missense differences between the Neandertal and modern humans sequences are H-Y genes, including KDM5D, the first H-Y gene characterized.32
It is tempting to speculate that some of these mutations might have led to genetic incompatibilities between modern humans and Neandertals and to the consequent loss of Neandertal Y chromosomes in modern human populations. Indeed, reduced fertility or viability of hybrid offspring with Neandertal Y chromosomes is fully consistent with Haldane’s rule, which states that “when in the [first generation] offspring of two different animal races one sex is absent, rare, or sterile, that sex is the [heterogametic] sex.”33
[b]Ca n’est que du : « estimation, pourrait, probablement, possible, suggérant, potentiellement, supposer… »
Et avec ces totales incertitudes, ces hypothèses tirées par les chromosomes, il sortent une publication délirante.
Oui, l’incompatibilité entre les Néandertaliennes et les Sapiens est claire et connue de tout le monde.
Elle n’a aucun rapport avec cette super hypothèse.
C’est des choses concrètes dont il faut parler et pas des hypothèses plus qu’obscurantistes.[/b]