In human genetics, Haplogroup J2 (M172) is a Y-chromosome haplogroup which is a subdivision of haplogroup J. It is further divided into two complementary clades, J2a-M410 and J2b-M12.

Origins

Haplogroup J2 is widely believed to be associated with the spread of agriculture from Mesopotamia. The age of J2 has been estimated as 18,500 +/- 3,500 years ago. Its distribution, centered in Western Asia and Southeastern Europe, its association with the presence of Neolithic archaeological artifacts, such as figurines and painted pottery, and its association with annual precipitation have been interpreted as evidence that J2, and in particular its J2a-M410 subclade belonged to the agricultural innovators who followed the rainfall. However, Di Giacomo stressed the role of post-Neolithic migratory phenomenon, specifically that of the Greeks, as being even more important in the dispersal of Hg J2.

Distribution

Haplogroup J2 is found mainly in the Fertile Crescent, the Caucasus, Anatolia, the Balkans, Italy, the Mediterranean littoral, the Iranian plateau, and Central Asia. More specifically it is found in Iraq, Syria, Lebanon, Turkey, Israel, Palestine, Greece, Italy and the eastern coasts of the Iberian Peninsula, and more frequently in Iraqis 29.7% (Sanchez et al. 2005), Lebanese 25% (Semino et al 2004), Palestinians 16.8% (Semino et al 2004) , Syrians 22.5% (Luis et al. 2004), Sephardic Jews 29%, Kurds 28.4%, Jordan 14.3%, Oman 15% (Di Giacomo et al. 2004) & 10% (Luis et al. 2004), UAE 10.4%, Yemen 9.7%, in Israel, in Palestine, and in Turkey.

J2 is found at very high frequencies in the peoples of the Caucasus - among the Georgians 21%-72%, Azeris 24%-48%, Ingush 32%, Chechens 26%, Balkars 24%, Ossetians 24%, Armenians 21.3%-24%, and other groups.

In Europe, the frequency of Haplogroup J2 drops dramatically as one moves northward away from the Mediterranean. In Italy, J2 is found with regional frequencies ranging between 9% and 36%. In Greece, it is found with regional frequencies ranging between 11% and 46%. Frequencies are high in Turkey, approximately 24% of Turkish men are J2 according to a recent study, with regional frequencies ranging between 13% and 40%. Combined with J1, up to half of the Turkish population belongs to Haplogroup J.

It has been proposed that haplogroup subclade J2a-M410 was linked to populations on ancient Crete by examining the relationship between Anatolian, Cretan, and Greek populations from around early Neolithic sites. Haplogroup J2b-M12 was associated with Neolithic Greece (ca. 8500 - 4300 BCE) and was reported to be found in modern Crete (3.1%) and mainland Greece (Macedonia 7.0%, Thessaly 8.8%, Argolis 1.8%) .

Sephardic Jews have about 29% of haplogroup J2 and Ashkenazi Jews have 23%, or 19%. It was reported in an early study which tested only four STR markers that a small sample of Italian Cohen belonged to Network 1.2, an early designation for the overall clade now known as J2a4, defined by the deletion at DYS413. However, a large number of all Jewish Cohens in the world belong to haplogroup J1 (see Cohen modal haplotype).

J2 subclades are also found in Iran, Central Asia, and South Asia.

Haplogroup J2 has been shown to have a more northern distribution in the Middle East, although it exists in significant amounts in the southern middle-east regions, a lesser amount of it was found when compared to its brother haplogroup, J1, which has a high frequency southerly distribution. This suggests that, if the occurrence of Haplogroup J among modern populations of Europe, Central Asia, and South Asia does reflect Neolithic demic diffusion from the Middle East, the source population is more likely to have originated from Anatolia, the Levant or northern Mesopotamia than from regions further south.

Haplogroup J2a-M410 in India was found to be largely confined to the upper castes with little occurrence in the middle and lower castes, but a new study has found it at higher percentages (10%) among the Tharu indigenous people of Terai, Nepal.

A substantial presence of J2b is found in the Balkans and neighboring parts of Greece in the West, and in both tribal and caste populations of the Indian subcontinent to the East. The high variance of J2b2 in South Asia indicates a probable pre-Neolithic migration.

Subdivisions

Haplogroup J2 is subdivided into two complementary sub-haplogroups: J2a, defined by the M410 genetic marker, and J2b, defined by the M12 genetic marker.

Below are the subclades of Haplogroup J with their defining mutations, according to the ISOGG tree (as of April 2009). Note that the descent-based identifiers may be subject to change, as new SNPs are discovered that augment and clarify the tree.

• J2 (M172) Typical of populations of the Near East, Southeast Europe, Southwest Asia and the Caucasus, with a moderate distribution through much of Central Asia, South Asia, and North Africa
  • J2*
  • J2a (M410)
    • J2a*
    • J2a1 (not currently in use by ISOGG)
    • J2a2 (M340)
    • J2a3 (P279)
    • J2a4 (DYS413≤18, L26/S57, L27)
      • J2a4*
      • J2a4a (M47, M322)
      • J2a4b (M67)
        • J2a4b*
        • J2a4b1 (M92, M260)
          • J2a4b1*
          • J2a4b1a (M327)
        • J2a4b2 (M163, M166)
      • J2a4c (M68)
      • J2a4d (M319)
      • J2a4e (M339)
      • J2a4f (M419)
      • J2a4g (P81)
      • J2a4h (L24)
        • J2a4h*
        • J2a4h1 (L25)
          • J2a4h1*
          • J2a4h1a (DYS445≤7)
            • J2a4h1a*
            • J2a4h1a1 (L70)
              • J2a4h1a1*
              • J2a4h1a1a (M137)
              • J2a4h1a1b (M289) (location under DYS445≤7 uncertain)
              • J2a4h1a1c (M318)
        • J2a4h2 (M158) (location under L24 uncertain)
  • J2b (M12, M102, M221, M314)
    • J2b*
    • J2b1 (M205)
    • J2b2 (M241)
      • J2b2*
      • J2b2a (M99)
      • J2b2b (M280)
      • J2b2c (M321)
      • J2b2d (P84)
      • J2b2e (DYS455≤9)

References

1. Sanghamitra Sengupta et al. (2006), Polarity and Temporality of High-Resolution Y-Chromosome Distributions in India Identify Both Indigenous and Exogenous Expansions and Reveal Minor Genetic Influence of Central Asian Pastoralists, American Journal of Human Genetics, 78:202-221
2. Ornella Semino et al., "Origin, Diffusion, and Differentiation of Y-Chromosome Haplogroups E and J: Inferences on the Neolithization of Europe and Later Migratory Events in the Mediterranean Area," American Journal of Human Genetics 74:1023–1034, 2004.
3. R. King and P.A. Underhill (2002), Congruent distribution of Neolithic painted pottery and ceramic figurines with Y-chromosome lineages, Antiquity 76:704-714
4. J. Chiaroni et al. (2008), Correlation of annual precipitation with human Y-chromosome diversity and the emergence of Neolithic agricultural and pastoral economies in the Fertile Crescent, Antiquity Volume: 82 Number: 316 Page: 281–289
5. F. Di Giacomo et al. (2004), Y chromosomal haplogroup J as a signature of the post-neolithic colonization of Europe, Human Genetics 115(5):357-71.
6. I. Nasidze et al. (2003), Testing hypotheses of language replacement in the Caucasus: evidence from the Y-chromosome, Human Genetics 112(3):255-61.
7. N. Al-Zahery et al., "Y-chromosome and mtDNA polymorphisms in Iraq, a crossroad of the early human dispersal and of post-Neolithic migrations," Molecular Phylogenetics and Evolution (2003)
8. Pierre A. Zalloua et al., "Y-Chromosomal Diversity in Lebanon Is Structured by Recent Historical Events," The American Journal of Human Genetics 82, 873–882, April 2008.
9. F. Di Giacomo et al. (2003), Clinal patterns of human Y chromosomal diversity in continental Italy and Greece are dominated by drift and founder effects, Molecular Phylogenetics and Evolution 28(3):387-95.
10. Cadenas et al. (2008), Y-chromosome diversity characterizes the Gulf of Oman, European Journal of Human Genetics (2008) 16, 374–386
11. Wikipedia article: Archaeogenetics of the Near East#Crete
12. D. Behar et al. (2004), Contrasting patterns of Y chromosome variation in Ashkenazi Jewish and host non-Jewish European populations, Hum Genet. 2004 Mar;114(4):354-65
13. P. Malaspina et al. (2001), A multistep process for the dispersal of a Y chromosomal lineage in the Mediterranean area, Ann Hum Genet. 2001 Jul;65(Pt 4):339-49
14. Sengupta, 2006. Polarity and Temporality of High-Resolution Y-Chromosome Distributions in India Identify Both Indigenous and Exogenous Expansions and Reveal Minor Genetic Influence of Central Asian Pastoralists http://hpgl.stanford.edu/publications/AJHG_2006_v78_p202-221.pdf
15. Simona Fornarino et al, "Mitochondrial and Y-chromosome diversity of the Tharus (Nepal): a reservoir of genetic variation," BMC Evolutionary Biology 9:154, 2009.

Bibliography

External links

• Y-Haplogroup J DNA Project
• J2 Y-DNA Project
• Haplogroup J2 blog
• J-l24 (J2a4h) Y DNA Project (Admin:Al Aburto,Co-Admins:David Dugas, Kamel Gazzah)
• In Lebanon DNA may yet heal rifts