August 21, 2014

Neandertal demise followed contact with modern humans (but not immediately)

Important:
Southern Iberia has been held to represent an exception to a wider European pattern21, with late survival of Neanderthals previously argued at sites such as Gorham’s Cave, Gibraltar22. We could not reproduce any of the late dates from sites in this region15 (Supplementary Methods) and it is apparent that many previous determinations underestimate the real age. It is unclear how long Neanderthals persisted in southern Iberia15.

Nature 512, 306–309 (21 August 2014) doi:10.1038/nature13621

The timing and spatiotemporal patterning of Neanderthal disappearance

Tom Higham et al.

The timing of Neanderthal disappearance and the extent to which they overlapped with the earliest incoming anatomically modern humans (AMHs) in Eurasia are key questions in palaeoanthropology1, 2. Determining the spatiotemporal relationship between the two populations is crucial if we are to understand the processes, timing and reasons leading to the disappearance of Neanderthals and the likelihood of cultural and genetic exchange. Serious technical challenges, however, have hindered reliable dating of the period, as the radiocarbon method reaches its limit at ~50,000 years ago3. Here we apply improved accelerator mass spectrometry 14C techniques to construct robust chronologies from 40 key Mousterian and Neanderthal archaeological sites, ranging from Russia to Spain. Bayesian age modelling was used to generate probability distribution functions to determine the latest appearance date. We show that the Mousterian ended by 41,030–39,260 calibrated years BP (at 95.4% probability) across Europe. We also demonstrate that succeeding ‘transitional’ archaeological industries, one of which has been linked with Neanderthals (Châtelperronian)4, end at a similar time. Our data indicate that the disappearance of Neanderthals occurred at different times in different regions. Comparing the data with results obtained from the earliest dated AMH sites in Europe, associated with the Uluzzian technocomplex5, allows us to quantify the temporal overlap between the two human groups. The results reveal a significant overlap of 2,600–5,400 years (at 95.4% probability). This has important implications for models seeking to explain the cultural, technological and biological elements involved in the replacement of Neanderthals by AMHs. A mosaic of populations in Europe during the Middle to Upper Palaeolithic transition suggests that there was ample time for the transmission of cultural and symbolic behaviours, as well as possible genetic exchanges, between the two groups.

Link

4 comments:

terryt said...

"Comparing the data with results obtained from the earliest dated AMH sites in Europe, associated with the Uluzzian technocomplex5, allows us to quantify the temporal overlap between the two human groups. The results reveal a significant overlap of 2,600–5,400 years (at 95.4% probability). This has important implications for models seeking to explain the cultural, technological and biological elements involved in the replacement of Neanderthals by AMHs. A mosaic of populations in Europe during the Middle to Upper Palaeolithic transition suggests that there was ample time for the transmission of cultural and symbolic behaviours, as well as possible genetic exchanges, between the two groups".

Possibly the most sensible comment on the subject I've ever read.

Grey said...

Could malaria be something to do with this?

If AMH moved north because of the climate getting warmer then malaria would have moved north also.

http://www.ata.org.tn/fichier_PDF/Article2.pdf

A review on the genetics of Sardinia mentions that malaria resistance like thalassemia has a distinct pattern of high values in the coastal regions (which were malarial until the late 1940s) and much lower values in the central mountains.

"The distribution of the two alleles is not uniform throughout the island and a
negative and highly significant correlation with altitude was found (Siniscalco et al.,
1966; Vona and Porcella, 1984). The villages mainly affected by the presence of the two
mutants are those of the plains and the coastal hills. The mountainous regions have
lower frequencies of the two alleles. This correlation is supported by the trend of the
two genes in the populations distributed along an axis running from the gulf of Oristano,
in the west of the island, across the central mountainous area, to the eastern coastal side.
The frequencies are very high in the two coastal sides and decrease sharply towards the
central mountainous area (Bodmer and Cavalli Sforza, 1977)."



As malaria resistant adaptation often seem to have very negative side effects then if a population moved out of Africa into the colder north they might lose the malaria resistance genes they had originally. So if it got warmer again and malaria spread north they'd have a problem whereas the newly arrived AMH wouldn't as they'd still retain theirs.

I don't suppose malaria leaves detectable signs in ancient bones?

Ed T. said...

Has anyone estimated the number of calories it would take to support a Neanderthal? Suspect it might be more than a modern human needs. In which case it would be interesting to model what happens to populations of both when competing for limited food resources...

Iridio said...

I am wondering what happened with the upper arqueological levels in the El Esquilleu Cave in Northern Spain, with supposedly Mousterian industry at 23,000 B.C.