Originally Posted by
sparkey
A Germanic spread of I2a-Din (and I2c-B!) is certainly not one I've thought about yet. It would explain the youngness of both. I feel like the center of diversity of I2a-Din is too far East for that theory to work, though... there is no spike of diversity, or even significant presence, of I2a-Din in traditional proposals for the Ostrogothic launching points. The closest diversity spike is Austria, which I admit I don't have an immediate answer for. I2c, meanwhile, has no detectable presence anywhere near the Ostrogothic launching points, the closest being the extra-diverse but very low-frequency bit in Germany, or maybe the extra-young (in fact, too young) Jewish bit in Eastern Europe. So I'm inclined to dismiss both proposals.
The Gepids run into the same problems as the Ostrogoths.
I still think that most I1 in the Balkans (and it's not totally insignificant) is Ostrogothic in origin, though.
The rest of your arguments are solid, Haustor. I think you're too quick to dismiss the presence of I2a-Din throughout the modern Slavs, including North Slavs, though (around 10% in Russians, for example).