@bicicleur, that is the case, we have a lot of farmer Y DNA but very few of neolithic herders, and when we have, like that of the Trocs, relation of Hg change dramaticaly. For the Celtic spread I follow archaeologists and linguists linking it to the Urnfield / Hallstadt / Laténe complex... which explain satisfactory the expansion of such languages: as for IE it's not necessary Yamna, for Celtic is not necessary BB.
indeed IMO Els Trocs is not related to Cardial/Impressed Ware neolithic
they were herders and maybe the came from Africa and crossed the Gibraltar strait
there was a 2nd wave of neolithic invasion in Europe, maybe from SW Asia, maybe from the Carpathian Basin
the brought herding and oxens as draught animals
but the Y-DNA of megalithic sites, Sopot and TRB is not much different from the early neolithic European Y-DNA
as for the spread of Celtic there are a few questions :
Early Bronze | Northern Ireland | Glebe, Rathlin Island [Rathlin1] | M | 2026–1885 BC | R1b1a2a1a2c1g | L21/M529/S145 > DF13/S521 > DF21/S192 | U5a1b1e | Cassidy 2015 |
Early Bronze | Northern Ireland | Glebe, Rathlin Island [Rathlin2] | M | 2024–1741 BC | R1b1a2a1a2c1 | L21/M529/S145 > DF13/S521 | U5b2a2 | Cassidy 2015 |
Early Bronze | Northern Ireland | Glebe, Rathlin Island [Rathlin3] | M | 1736–1534 BC | R1b1a2a1a2c | L21/M529/S145 | J2b1a | Cassidy 2015 |
this is 2000 BC
their Y-DNA is the same as today in Ireland, Brittany, Wales and eastern England
those people spoke Celtic
did they allready 2000 BC?
it can't be explained by Urnfield etc.
these people had trade relations with Nordic bronze before Urnfield
after the invasion of Urnfield people trade with Nordic bronze was disturbed but there was the 'Atlantic bronze' trade
this would perfectly explain the distribution of R1b-L21 over Europe
then there is the question of the king of Tartessos who had a Celtic name (allthough the population didn't speak Celtic)