J1. M267 The J1 subclade of Haplogroup J is abundant in the Arabian Peninsula (10-75%), Africa (5-30%) and Southwest Asia (5-10%). It has a TMRCA estimated at ~10kya and expansion from 10-5 kya. J1 is common among Arab populations and has a substantial drop-off in non-Arab countries. For example, in a study of Lebanese groups, J1 was found at more than a twice the frequency in Muslim versus non-Muslim Lebanese. Northern source, i.e. the Caucasus of J1 presumed for the populations in the Arabian Peninsula. The J1 subclade is found in Africa, but limited to the North and Northeast corner (Horn of Africa) adjacent to Sinai and Arabian Peninsulas. It is not found in Sub-Saharan populations. Semitic- and Caucasian-language populations in Africa have a typically high frequency of J1. Examination of the results for the phylogeography of subclade J1 and its STR variation support two African migrations – an earlier one during the Neolithic era driving Southward toward Ethiopia and a later one (7th century AD) traveling North. The second migration may have been spread by Arab slave trade, perhaps Bedouin groups. Further propagation was likely provided by Muslims in 6th century AD. The J1 subclade is fairly common in Iran – as is J2 (~10% and ~20%, respectively). Iran is situated in an area that witnessed the migration of populations bearing both of these subclades. The J1 subclade is also common among Jewish populations (a similar J1 to J2 frequency profile as in Iran). The high frequency of the J1 subclade in Ashkenazi Jews versus non-Jews in Europe has led to the idea that this haplogroup is associated with the foundation of this population. J1 is found at low levels in European Mediterranean countries (e.g. ~5% in Portugal) and bears a Y-chromosome signature closer to a Jewish Modal Haplotype (Cohanim Modal Haplotype) than the Arabian or Galilee Modal Haplotype. Since little gene flow has been found from North Africa into Europe, the presence of J1 in the European Mediterranean may have been spread by sea-faring Greeks or Phoenicians (general area of present day Lebanon) through the Mediterranean Sea. It should be noted the sister clade J2 is higher in Portugal and other Mediterranean countries and the speculation for maritime spread from the Aegean also exists for the J2 subclade. The J1 M267 SNP is associated with the DYS458.2 allele (either a GA deletion or AA insertion in a GAAA repeat) and with an unusually short DYS388 allele (13 repeats rather than a typical ≥15 repeats). These STR variants have been used as genetic markers and their co-inheritance with the M267 SNP indicates they are linked genetically. The J1 subclades, listed below, have low frequencies detected so far and are likely to be minor subclades.
Posted on: Fri, 20 Sep 2013 21:59:28 +0000
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