As pointed out to me, by Rob, it appears there is a new date for a sample from Barcin Hoyuk, in Turkey. This sample (I0707) is now dated to the Mesolithic (9650-9291 cal BCE). This is a huge find, as it changes the view of the way agriculture got to the region, all together. I feel that this may be the biggest thing included in the Wang et al (2018) paper, but others interested in Indo-European studies may disagree. I have contacted the authors to verify this, just to be sure.
Nearly everyone has interpreted the appearance of agriculture in NW Anatolia to some other place in Anatolia, via migration. This often includes Hacilar and Catalhoyuk. This is based on some similarities in pottery, but does ignore the differences in domestic plants in use, as well as the architecture in NW Anatolia.
With this new sample, it appears we may have our first evidence of agriculture and animal husbandry being adopted by a local, or near-local Mesolithic group. Using data available from Mathieson et al (2018) and Lazaridis et al (2016), I decided to compare how this Mesolithic sample compares to the farmers of Barcin, 3000 years later. The results were quite shocking.
Anatolia_N and Meso_Anatolia Form a Clade, With Respect To Other Groups
The following D-stats detail that the average of all farmers and the Mesolithic Barcin sample are nearly identical, only deviating with a Z>2 for Ukraine_N, towards Anatolia_N.
F3-ratio test for Potential Admixture
In agreement with the D-stats, there is only one stat that sees a Z-score >3 for admixture going from Meso_Anatolia to Anatolia_N. This was with Ukraine_N, suggesting that there is potentially a pop nearby that contains some of this ancestry. Possibly from around Bulgaria.
|Source 1||Source 2||Target||f_3||std. Error||Z||SNPs|
qpAdm Model of Anatolia_N Using Meso_Anatolia
This testing also showed agreement with D-stats and f3-ratio. Anatolia_N was modeled as a two-way mixture of Meso_Anatolia and Ukraine_N. For the outgroups, I have used Chimp, Iron_Gates, Ust_Ishim, EHG, West_Siberia_N, IBM (Iberomaurusians), Ganj_Dareh_N, Brazil_LopaDoSanto_9600BP, Natufian, and CHG.
The test was also successful in modeling Anatolia_N as a mix of about 97 percent Meso_Anatolia, with 3 percent admixture from a source similar to Ukraine_N.
numsnps used: 520478
best coefficients: 0.970 0.030
std. errors: 0.017 0.017
fixed pat wt dof chisq tail prob
00 0 8 5.839 0.665269
qpGraph Modeling of Anatolia_N
As a final check, I ran qpGraph to see if there would be more confirmation of the above stats.
While more complex, I tried to include several pops as the outgroups, or admixture sources in the creation of Meso_Anatolia, and how this compares to Anatolia_N. I have included Chimp as the outgroup, with CHG, Ust_Ishim, Natufians, Iron_Gates, and Ukraine_N as potential sources of ancestry and additional admixture for Anatolia_N. This first graph, is the base of Meso Anatolia, where a mix of a pop similar to Iron_Gates, Natufians, and CHG does well to create the potential source population at Barcin Hoyuk during the Mesolithic.
For the next graph, I included Anatolia_N, connected to the Mesolithic Barcin sample. Essentially seeing if they are a clade, as this was the heavy favorite in Z-score, when not attaching Anatolia_N to any one population.
These two populations did indeed, essentially form a clade. There isn’t a great deal of reason to improve this, but with the stat connecting Anatolia_N to Ukraine_N, I figured I would explore that and see if improved the fit.
This final graph actual showed the same thing as qpAdm, and in agreement with D-stats and f3-ratio, with Anatolia_N needing admixture from a population similar to Ukraine_N, at a rate of 3 percent. Depending on the response from the authors, to verify the dating of the sample, it does appear that farming was a local event, potentially adopted by the previous Mesolithic inhabitants.
While this is only based on a single sample, there is enough here to suggest the possibility that the Neolithic package arrived in Barcin through cultural exchange, rather than demographic movements. More high quality samples from other parts of Anatolia will help to see if this holds up. Comparison between the shotgun Boncuklu and Barcin samples may have had some artifact affecting the stats showing movements from the Levant. Soon, I will look back at Europe, as the picture there looks much more complex, with some significant stats towards other populations other than hunter gatherers. This could include from the Levant and Eastern Anatolia.
Mathieson et al. (2018) The genomic history of southeastern Europe. Nature volume 555, pages 197–203 (08 March 2018) https://www.nature.com/articles/nature25778
Lazaridis et al (2016) Genomic insights into the origin of farming in the ancient Near East. Nature volume 536, pages 419–424 (25 August 2016) https://www.nature.com/articles/nature19310
Wang et al. (2018) The genetic prehistory of the Greater Caucasus. https://www.biorxiv.org/content/10.1101/322347v1.supplementary-material