1 out of 1 members found this post helpful.
I'd say, J2 was highly agriculturalist. Their epicenter was and is in Fertile Crescent, spreading nicely and continuously in southern and western Europe, with diminishing in Carpathian Mountains and other mountainous areas.
Their crops, early wheats where not as advanced as today's varieties, so it is logical that J2 spread was limited in northern Europe where climate was vastly different than the area of their inception. Plus North was already populated by successful herders of R1a haplogroup, the steep competition.
J2 is the richest in Greece and Italy. This might mean that well off agricultural societies were behind the engine of first strong city-states and consequently the first European empires of Greece/Macedonia, and Romans. Eventually they also became sea going people, but it was more around Bronze Age and later.
I have a feeling that J2 was most numerous of all haplogroups in southern Europe in mid Neolithic till the arrival of IE.
J2 also matches the borders of Roman Empire. Obviously RE helped J2 flow within it's borders, but I think it didn't do much difference. The truth might be that RE conqured these areas with rich populous farming communities (already with a lot of J2) and wasn't much interesting in more spares, poorer and wiled north.
1. First farmers in Europe
2. No other HG matches spread of early farming that well.
3. Rich agricultural engine behind Greece and Rome
4. Most populous among HG in mid Neolithic till IE R1b arrival, and declining since Bronze Age (percentile wise)
5. J2 in Northern Europe might be more Jewish than early farmers.