I wouldn't read too much into the Late Bronze Age J2a1 sample from Hungary (c. 1200 BCE). The Indo-Europeans had been in the region for nearly 2000 years by then, and it could very well have been a foreigner or an assimilated person from a non-IE culture. After all three Unetice samples tested in this new study turned out to be assimilated local I2 lineages, not steppe lineages.
That could be but which non neolithic farmer population could have come before the Indo Europeans and brought this Haplogroup? There is always a likelyhood for other scenarios but from the data we have so far, an Indo European origin looks like the most likely one.
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No one knows precisely what cataclysmic events took place around 1200 BCE, but I would bet that this corresponds to an expansion of J2a people in the Eastern Mediterranean, and that the Sea Peoples were probably predominantly J2a people. After all, all the great ancient seafaring civilizations all presumably had high percentages of J2a, including the Phoenicians who just happen to emerge around 1200 BCE.
Yes but as you said yourself, Sea People emerged later. And I don't know of any other possible migration to Hungary which could have brought J2a there.
One hypothesis of mine is that the Sea Peoples were descended from the Minoan civilization, which had just collapsed c. 1450 BCE. The fall of the Minoan state might have led to Minoan people turning to piracy and raiding the coasts of the East Mediterranean, from Sardinia to the Levant. The Trojans, whose city had been destroyed by the Mycenaeans c. 1200 BCE, may well have been a mixture of R1b-L23 and J2a people, and Trojans who escaped may also have been among the Sea Peoples who sought revenge on Mycenaean Greece and caused its downfall less than 100 years later.
I don't see why Minoans would end up in Hungary especially not just 100 years after their collapse and be able to mix so much with the local population in Hungary, that their genetic make up turns totally French like. Also are we speculating that Sea People gave this J2a individual his ANE- That doesn't seem very likely to me, especially not if all the other late Neolithic, Bronze Age samples from the same region are a mix of WHG and ENF, but have no ANE yet. From who should the J2a individual have gained it's ANE?
In such a context, it would be unreasonable to label a Hungarian J2a1 as necessarily Indo-European.
Not necessary yes, but allot more speaks for an Indo European, than any other theoretical origin.
The point here is, we having two Bronze Age samples from Hungary and only the J2a sample showing ANE admixture and the arrival of ANE admixture in Hungary beeing connected with the arrival of J2a.
Note I am not claiming that J2a came exclusively with Indo Europeans. There are multiple origins of J2a for sure.
But we will see in future with more samples.