In human genetics, Haplogroup J-M172 or J2 is a Y-chromosome haplogroup which is a subclade (branch) of haplogroup J-M304. Haplogroup J-M172 is common in modern populations in Western Asia, Central Asia, South Asia, Europe and North Africa. It is thought that J-M172 may have originated between the Caucasus Mountains, Mesopotamia and the Levant.