Around 28,000 years ago typhological Neanderthal traits cease to exist. However some old genetic traits exist and are subject of ongoing research.

The first attested archaic Homo sapiens outside Africa are found at Skhul and Qazfah (Israel) and are dated about 100 kya, though the Middle East seems to have been occupied by Neanderthals until 40 kya, when the Cro-Magnons appeared again in the region and flowed into Europe.

Interaction may have occurred at any time along the fringes of the Neanderthal expanse, and ultimately anywhere they met with the Cro Magnon advance. Currently, the expansion of the first anatomically modern humans into Europe cannot be located by diagnostic and well-dated anatomically modern human fossils "west of the Iron Gates of the Danube" before 32 kya.^[1] In Lagar Velho, Neanderthal skeletons of younger dating have been found with mixed traits, in Southern Iberia.^[2][3]

The Mousterian culture is essentially associated with Neanderthal. There is no agreement on the association of early Aurignacian culture to any specific physical human type, including figurative art found at Vogelherd.^[4] In between, ca. 45 kya, Neanderthal remains became increasingly associated with cultural artifacts such as perforated animal-tooth pendants (known as the Châtelperronian culture) and traditionally this has been regarded evidence of acculturation of the Neanderthals.

New assessments are consistent with the hypothesis of an original and independent cultural evolution of Western Europe's late Neanderthals.^[5]

Genetics

The genetic variation at the microcephalin gene, a critical regulator of brain size whose loss-of-function by damaging mutations may also cause primary microcephaly, is claimed to be the most compelling evidence of admixture thus far. One type of the gene, dubbed haplogroup D having an exceptionally high worldwide frequency (~70%), was shown to have a remarkably young coalescence age to its most recent common ancestor ~37,000 years ago. The remaining types (non-D) coalesce to ~990,000 years ago, while the separation time between D and non-D was estimated at ~1,100,000 years ago. An evolutionary advance was assumed, even though positive selection was never as all-decisive as to wipe out the remaining 30% of non-D haplogroups (in which case no introgression could have been suggested) and as for now, a measurable genetic advance has not been attested.^[6]

Both the worldwide frequency distribution of the D allele, exceptionally high outside of Africa but low in sub-Saharan Africa (29%) that suggests involvement of an archaic Eurasian population, and current estimates of the divergence time between modern humans and Neanderthals based on mitochondrial DNA (mtDNA), are in favor of the Neanderthal lineage as the most likely archaic Homo population from which introgression into the modern human gene pool took place. ^[7][8]

The case for fertile reproduction recently revived by studies that claim signs of admixture (introgression), finding unusually deep genealogies in highly divergent clades (genetic branches). However, most of the times this feature can be explained by balancing selection. For instance, estimates on the gene for red hair vary from 20,000 to 100,000 years ago^[9][10], though there is no compelling evidence to assume red hair didn't coexist with other hair colours all along within one and the same population. Moreover, Lalueza-Fox and colleagues found a different variant of the same gene in their Neanderthal samples, that similarly disabled a protein to the same effect.^[11]

Footnotes