In human genetics, Haplogroup J2 (M172) is a Y-chromosome haplogroup.
Haplogroup J2 is widely believed to be associated with the spread of agriculture from Anatolia (),(). This connection is supported by its age (18,500 +/- 3,500 thousand years ago) (), which is very close to the beginning of the Neolithic, its distribution, which is centered in West Asia and Southeastern Europe, as well as its association with the presence of Neolithic archaeological artifacts, such as figurines and painted pottery ().
It is a descendant haplogroup of [haplogroup J (Y-DNA)? haplogroup J].
Haplogroup J2 is found frequently in Greece and Italy (), in Turkey (), and in the Caucasus region ().
J2 is also found in India, where the subclade [Haplogroup J2b2 (Y-DNA)? J2b2] is widespread and another subclade [Haplogroup J2a (Y-DNA)? J2a] is mainly restricted to North-West of the subcontinent population or later migrants to South and East India like Brahmins (). This, together with its believed Anatolian origin, may be suggestive that it was originally a part of the Proto-Indo-European gene pool. According to the theory of Colin Renfrew, Indo-European languages spread from an Anatolian homeland (). It should, however, be noted, that there is no perfect correlation between language families and genetic markers.
Jews and Arabs also possess J2, as do Kurds and other Middle-Eastern populations (). Typically, these populations of the Middle East have a higher frequency of the related haplogroup J1 than the populations of Europe and India where J2 is much more frequent.
Haplogroup J2 is subdivided into two complementary sub-haplogroups: J2a, defined by the M410 genetic marker, and J2b, defined by the M12 genetic marker. A subclade of haplogroup J2a, defined by the M92 marker has been implicated in the ancient Greek colonization ().