Just something I noticed.
From previous papers, we already know that while the introgression of Steppe ancestry in Corded Ware (>70%) and Bell Beaker (~50% in most cases) is very great, the introgression into Southeastern Europe almost seems deccelerated, plateauing at around 30% in the middle to late Bronze Age overall. This makes the BA Hungarians look almost like French and Spanish autosomally, which is visible from David's PCA as the olive squares.
Image
This is corroborated by further data from Mathieson et al, who give us the following:
Their PCA is projected, which makes it difficult to predict the final clustering of the Balkan samples, but you can already see that the Balkan Bronze Age samples are between the Mako Hungary and Hungary LBA, and cluster exactly with Vatya, which in David's plot will make them cluster between Basque, Spanish and French, which is a very low level of Steppe ancestry considering how close they are to the steppe.Other Copper Age (~5000-4000 BCE) individuals from
the Balkans have little evidence of steppe ancestry, but Bronze Age (~3400-1100 BCE)
individuals do (we estimate 30%; CI: 26-35%).
More information about Vatya, including their low level of Steppe ancestry, can be found in the Allentoft et al Supplementary materials.
This quite surprising, given that the early Yamnaya migration into the Carpathian basin was given great importance in many theories. It also means that the migration through the balkans probably was not the source of Steppic ancestry into BB and CW, since they were less Steppic than the BB and CW themselves.
The situation is made even murkier if we look at the paternal haplogroups of the EBA Balkans. Here are their haplogroups from Supplementary Table 3 of Mathieson et al, along with their level of Steppe ancestry:
I2520: H2-L279. ~7% Steppe ancestry, 3336-3028 calBCE.
Grave goods, including crimson spondylus shell necklace, silver objects, and ceramic vessels, present. Head facing East.
I2176: I2a2a1b. ~10% Steppe ancestry, 3338-3025 calBCE.
I2175: I2a2a1b. ~6% Steppe ancestry, 3338-3015 calBCE.
Relatively tall pair, silver objects and ceramic vessels present, red ochre and sandstone present, head facing east.
Bul10: female; ~12% Steppe ancestry, 3090-2924 calBCE
Infant in an EBA ditch with vessels.
I2165: I2a2a1b. ~22% Steppe ancestry, 3020-2895 calBCE
Head to the east, colored with red ochre.
I2510: G2a2a1a2. 0% Steppe ancestry. 2906-2710 calBCE
Grave disrupted by another bronze age grave.
Bul6: I2a3. ~5% Steppe ancestry. 3400-1600 BCE
Bul8: I. ~5% Steppe ancestry. 3400-1600 BCE
Unearthed from beneath an actual round barrow.
These samples stand in great contrast to the Bulgarian Yamnaya sample, who is ~85% Yamnaya or so, and was geographically proximal to the Bulgarian samples. Not a single one of them are R1b or R1a.
The rest of the Balkan Bronze Age samples are >1 millenium later, and are comfortably Yamnaya-rich (>40%), with an R1a 80% Yamnaya individual, but in these earlier burials not even those from beneath the barrows are rich in Steppic ancestry, and the rest of them are not low social status individuals either.
This looks very weird and uncomfortable to me, in the context of the Kurgan theory as propounded by Mallory, Heyd and co--or at least their interpretation, with an early (and massive) migration into the Balkans playing a pivotal role.
What is going on? Anyone have any ideas? Perhaps Southeast Europe was late to be Kurganized, or kurganisation was fleeting, or there was a lot of social differentiation during the Kurganisation process, because the density of farmers was greater than in Northern and Western Europe? Or maybe the Kurganisation of SE Europe was unique in being less mediated demographically and more culturally, maybe due to a long history of contact?
P.S.
On the other hand, in the Vucedol, we have:
I4175: Female with U4a. ~50% Steppe ancestry. 3000-2700 BCE.
I3499: R1b1a1a2a2. ~25% Steppe ancestry. 2884-2666 calBCE.
I2792: G2a2a1a2a. 0 steppe ancestry. 2872-2617 calBCE
It seems like Vucedol has more steppic connections than the intervening cultures to the east of them.