If I1 migrated from the south and mutated into I2a in the north, how come there is no I2a in the north, and no I1 in the south, which would seem logical? Why did only I2a migrate back to the south and not I1 as well? And the most important thing, not Goth, but paleo-European, Goths are a young Germanic ethnicity sharing that genetic haplogroup with other ethnicities Slavic and Romanic, not a haplogroup as such.
In 2010 it was argued that I2a2a (The dominant Serbo/Croat genetic haplogroup) is too young not to have been a result of a sudden expansion. According to Kenneth Nordtvedt, a genetic genealogist, gene I2a2a arose not earlier than 2500 years ago in Eastern Europe. He has presumed this to be a consequence from the Slavic invasion of the Balkans, from the area north-east of the Carpathians since 500 CE. In 2011 Nordtvedt has confirmed I2a2a is not older than 2,800 years. In his last comments about Haplogroup I tree and the conjectured spread map, he locates the start of the I2a2a lineage around the middle course of the Vistula.
The research supports the archeological facts, as well as the Serbo/Croat Slavic migration theory.