G2a and J2 are West Eurasian, R1b can head back to Cambodia. The origin of J2 was in Europe.
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There is a Mesolithic sample in Italy with R1b (with a degree of ANE). Even then there are hints that Pre-LGM Balkan / Eastern Epigravettian Hunter-Gatherers harbored some J and likely some J2 alongside I-M170 and their respective subclades long before that lone R1b, it's pretty much a dead end sample.