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Haplogroup IJ (M429/P125) is a human Y-chromosome DNA haplogroup, a descendant branch of Haplogroup IJK (previously known as Haplogroup F-L15).〔(ISOGG Y-tree showing HG 'IJK' )〕 which in turn derives from Haplogroup F. The immediate descendants of IJ are Haplogroup I and Haplogroup J. Its sole sibling is K (which includes most of the world's male population). Haplogroup IJ derived populations account for a significant proportion of the pre-modern populations of Europe, Western Eurasia and North Africa. As a result of mass migrations during the modern era, they are now also significant in The Americas and Australasia. ==Origin== The estimated time to MRCA for the IJ clade is 38,500 (30.5–46.2 kya).〔T〕 The existence of the Haplogroup IJ node has been inferred from the fact that certain mutations are shared in common among all Y-chromosomes belonging to the descendant haplogroups I and J. Until very recently, the lack of examples of Haplogroup IJ * complicated any attempt to deduce the geographical location where Haplogroup IJ first appeared. Both Haplogroup I and Haplogroup J are found among modern populations of the Caucasus, Anatolia, and Southwest Asia tends to support the hypothesis that Haplogroup IJ derived from IJK in the vicinity of West Asia or the Middle East and subsequently spread throughout Western Eurasia. A recent study by Grugni et al. 2012 of genetic diversity in Iran found some examples of Haplogroup IJ (M429). These individuals were reported to be ancestral (negative) for the primary SNPs that define both haplogroup I (M170) and haplogroup J (M304) and therefore appear to represent a yet undefined genetic branch. Because only a select few SNPs were tested, one cannot rule out that these individuals would test positive for one of the other SNPs thought to be phyloequivalent to M170 and M304.〔(Dienekes’ Anthropology Blog: Huge study on Y-chromosome variation in Iran (Grugni et al. 2012) )〕〔(PLOS ONE: Ancient Migratory Events in the Middle East: New Clues from the Y-Chromosome Variation of Modern Iranians )〕 It may be difficult to draw conclusions given the relatively small number of haplogroup IJ samples that were discovered given the limited scope of testing that was done. The role of the Balkans as a corridor to Europe from the Near East is suggested by the phylogenetic unification of haplogroups I and J in IJ (M429). This proof of common ancestry suggests that IJ probably entered Europe through the Balkans sometime before the last glacial maximum. It probably split subsequently into J and I in the Middle East or Europe (in a typical disjunctive phylogeographic pattern. This apparent geographic corridor is likely to have supported subsequent gene flows, including some identified with early European farmers. An inference may also be made from the existence of the parent haplogroup IJK and its evolutionary distance from haplogroup HIJK, that both IJ (M429) and K (M9) arose closer to the Middle East than to East Asia. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Haplogroup IJ」の詳細全文を読む スポンサード リンク
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