J2 Bronze Age speculations: ancient J2b2 Balkan, J2a Caucasus, Anatolia & Mesopotamia

[ChrisR]

Eurogenes Hurrians and the others might give some insights on ancient J2 lands like the Caucasus, Anatolia, Mesopotamia and South Caspian:
Armenia_EBA (Early Bronze Age, Kura-Araxes) shows strong affinity to Caucasus populations, particularly those from the Northeast Caucasus. Speaking of J2 at least the following two dominant regional subclades should be involved: J2a-M67-Z7671 & J2a-Z6049-SK1321.
Armenia_MLBA (Middle Late Bronze Age) seems to have gotten influence from the Baltic and be related to the Sintashta culture which should be more related with Y-DNA R1a-Z93 movements (the majority of the 8% Armenian R1a men is Z93+).
The variation and people movement in the Bronze Age seems to have been considerable, so without more ancient samples we may not see all nuances.

The comments of Aram & CroMagnon mention the late Bronze Age Norabak Culture J2b2a as well as the two J2 Neolithic Hungary samples. Aram:

Albanians have the highest level of J2b2a in Europe and also score close affinity to Anatolia Chalcolithic and Kura Araxes. When exactly J2b2 reached South Balkans is unknown. It was absent in Euro-Anatolian Neolithic.

CroMagnon correctly states the two J2 Neolithic Hungary samples subclade is unknown.
Regarding the age of modern J2b2a in (South) Balkan we can make a good estimate by looking at the diverse Balkan results under Z597,Z628: both Z1296 and Y15058,CTS3617 have plenty of Balkan subclade diversity so this origin of Z597,Z628 is the most likely using Phylogeography. The diversity of the ancestral (xZ628) subgroups of Z585 as well Z600,Z590 and L283 is not yet high (focused on Francalacci Sardinian results) so they seem to have expanded from the Anatolian to the Italic territory without modern Balkan or West Asian diversity so far. More NextGenSequences from this area are needed. Sea migration or at least coastal migration should have played a considerable role, see also the few coastal East and South Mediterranean (possibly) L283 samples. Ages for J2b2a according to YFull YTree v4.09:
Separation from Asian J2b2b (Z2444): 13900 ybp
MRCA (founder) of J2b2a-L283: 5900 ybp (Chalcolithic/Copper Age)
Migration from Armenia/Anatolia to Balkan: 5900 ybp to 4300 ybp (late Copper Age to Early Bronze Age)
MRCA (founder) of Balkan J2b2a-Z597,Z628: 4300 ybp (Early Bronze Age)

All in all the case for Caucasus/Armenia and South-Caspian/Zagros as the J2(a & b) Homeland remains strong by using the current ancient DNA evidence. The Levant (Natufian culture) seems to be ruled out. For Mesopotamia and Northern Persian gulf coast (Gedrosia) we do not have enough ancient and modern data to say much. 15000 years old J2 is needed to get real evidence.

[Trojet]

Interesting read Chris!
Regarding J2b2a-L283 arrival to Balkans/Europe, I've had a very similar hypothesis for a while. In the Balkans we see a great deal of diversity of early subclades of J-Z628,Z597. So most likely it's an (early) Bronze Age arrival to SE Europe. A direct migration through the Black Sea from Armenia/Anatolia to Balkans is possible, considering the J2b2a-L283 (xZ627) ancient DNA sample from LBA Armenia. Though, we'll see how this turns out when we get some Bronze Age aDNA from Balkans and around.

There is also a Balkan sample (Kosovo Albanian), kit N112484, who through Geno 2.0 has tested as J-Z638 (xZ1296). This is a very interesting result, unless Geno 2.0 didn't report Z1296 correctly. At some point I'm planning on funding him a BigY assuming he is ancestral for Z1296 : https://www.yfull.com/tree/J-Z597/