Haplogroup J2 consists exclusively of two separate subclades: J2a-M410 and J2b-M12.
Crete, occupying the southmost of the Greek world has an M12/M172 ratio of 2.2% . This ratio is 20%  or 42.2% , a weighted average of 26%. In Northern Greece (Macedonia) it is 43.2% .
In Albania, the same ratio is 100% in the small sample of  and 54.6% as reported by , a weighted average of 55%.
In Bulgaria, the ratio is 28.6%  and in Romania, the ratio is 0% in the good sample of . In the Ukraine it is 32.9% 
According to , the ratio is high in Serbs (66.3%). The few Croatians and Herzegovinians belonging in haplogroup J2 belong to the M12 clade, giving a ratio of 100% [2,3]. Similarly in Poland (100%) , and Czech Republic/Slovakia (50%) .
The distinction between the Western and Eastern Balkans that I have spoken of before is clear in this regard. M12 clade comprises the majority of J2 in the West and the minority in the East. Moreover, Slavic speakers of continental Europe belong more to the M12 clade, whereas those bordering Black Sea are more inclined to have a low frequency of M12, including the non-Slavic Romanians who lack M12 altogether. In historical times, the Balkans were inhabited by several Indo-European peoples which could be classified in the macro-groups of Illyrians (west) and Thracians (east). Greek trade and settlement occurred in both the Adriatic and the Black Sea, but the Greek presence was probably heavier and more long-lasting (until recent times) in the latter region.
Italy resembles the Greek-Black Sea area. Southern Italy has a ratio of 12.4%, while Northern Italy has a ratio of 25% . North-Central Italy (35.7%), and two Calabrian samples (1%), and Sicily (0%). The latter two locations were Greek speaking for the major part of their recorded history.
Turkey resembles the Greek-Black Sea-South Italian area with an overall ratio of 7.1% . Turkey was primarily Greek, Armenian and Kurdish speaking before the arrival of the Altaic-speaking Turks. Before that, it was also home to a variety of languages, including several extinct languages of the Indo-European family such as Hittite, Luvian, Palaic, Lydian, Lycian, Phrygian, and Celtic.
 Di Giacomo (2004)
 Semino (2004)
 Pericic (2006)
 Cinnioglu (2004)