Update on J1-Z1842 and Kura-Araxes culture.

 Update on J1-Z1842 and Kura-Araxes culture.

The recent Agdzhoyan et al. paper about Dagestani people added some long waited details to the structure of the J1-Z1842 and its distribution.

We learned that beside ZS3114 and CTS1460 there is a third important branch in Z1842, which is very specific to Dagestan. Its ZS3042 which is absent in Armenians and apparently very rare in South Caucasus. In Yfull many Dargins and Kaitags are present in that branch.

Another important information is the branch ZS3114 which is more frequent in Lezgins than other Dagestani people. It has a more southern distribution. In Armenians its found almost exclusively among eastern Armenians. If the language of Lezgi speakers is related to this ZS3114 branch then this can support some linguistic theories making Lezgi-Udi group as the first split in Nakh-Dagestani family.

All this data forces us to rethink the origin of J1-Z1842 and place its locus of differentiation close to Eastern Caucasus range.

However I still dont think that the expansion of Z1842 started from the northeast of Caucasus. There are many arguments against such a theory. But one the most strongest is the autosomes of oldest Z1842 ancient DNA. They all have significantly lower levels of steppe ancestry than Areni cave preceding them. Its very hard to imagine that Z1842 lived for thousand years in the north and did not acquired substantial steppe ancestry.

What this data tell us is another possibility. The branch specific to Dagestan the ZS3042 could have diverged earlier with Chalcolithic culture Sioni - Ginchi (5000-4000bc). Ginchi is a site on north Caucasus with similar pottery as in Sioni (Georgia). As for the parallel CTS1460 which has a great diversity in South Caucasus/Near East and was found in multiple ancient Kura֊Araxes sites is a genuine Kura-Araxes lineage. Its TMRCA in Yfull also more realistically fits to the spread of Kura-Araxes culture.

And finally about the origins of KA culture itself. Recent claims of KA pottery in Chalcolithic levels of Areni, Ovčular tepesi in Nakhichevan and in some sites in Turkey combined with the fact the extra CHG/J1 ancestry in KA samples was from more eastern regions means that the formation of KA culture and its later spread are not necessarily done by the same population. So there must be two distinct KA with probably two distinct autosome profiles.

Alternatively the extra CHG could still be from unsampled forest mountain regions of Lori and Tavush. They could harbor a hunter gatherer (Aknashen like) enclave different from Areni and Shulaveri culture. But even with this scenario the contradiction is not solved.

According Passerini et al. the oldest KA was in lowlands with collective kurgan burials. Only starting from 3300BC highland KA with permanent settlements emerged. This later KA that we can call KA 2 can have a different locus (left side of Kur river?) and population (CHG rich) than the first one. KA 1 in the other side can be more related to Areni type population. This hypothesis obviously require confirmation by ancient DNA