So there are several threads, all recently active, where the focus of the conversation has turned to (often passionate) discussions about how I2a1b1a-Din, the most common Haplogroup I subclade in the Balkans, got to the Balkans. But we seem far from reaching consensus on this forum, so here's a poll to at least put our finger to the wind regarding the direction this forum is leaning.

I've included as options several different possibilities I've read:

Paleolithic continuity: I2a-Din has been in the Balkans since the Paleolithic, and present distribution outside of the Balkans is the result of migrations out of it. There is direct geographic continuity for this clade from Gravettian culture and/or the Balkans Ice Age refuge. Proponents point out the age of Haplogroup I and the frequency distribution of I2a-Din. I've read Maciamo articulate this view, but I'm not sure if he still holds it.

The Early Indo-Europeans: I2a-Din was brought to the Balkans by the Indo-European migrations. It was part of the "original" collection of Y-DNA of Indo-Europeans. Proponents point out that everywhere that Haplogroup I is dominant nowadays speaks an IE language. How yes no was fond of this theory for a while.

Sea Peoples: I2a-Din was brought to the Balkans by seafaring groups not otherwise mentioned in this poll. The migration happened before history or early in history. Proponents point to the frequency distribution and the lack of historical verification for later migrations. How yes no explored this idea, and recently Pyrub has advocated it.

The Sarmatians: I2a-Din was brought to the Balkans by the Sarmatians. Proponents of this view cite the STR dating estimate for the clade, the apparent Asian spillover of it, and the historical attestation to Sarmatians (but not Slavs) in the Balkans. Bodin has been the most vocal advocate of this theory here.

The Slavs: I2a-Din was brought to the Balkans by expanding Slavs in the 1st millennium CE. Proponents cite the age of the clade, expert STR diversity analysis by people like Nordtvedt and Verenich, and dispute that history doesn't verify the Slavic expansions. I have supported this view, as have a few other posters.

If you believe that multiple expansions resulted in the current I2a-Din distribution in the Balkans, indicate which you feel brought most or had the greatest impact. If you feel that the data is deficient, make your best educated guess.