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In human mitochondrial genetics, Haplogroup N is a human mitochondrial DNA haplogroup. An enormous haplogroup spanning many continents, the macro-haplogroup N, like its sibling M, is a descendant of haplogroup L3. All mtDNA haplogroups found outside of Africa are descendants of either haplogroup N or its sibling haplogroup M. M and N are the signature haplogroups that define the out of Africa migration and the subsequent spread to rest of the world. The global distribution of haplogroups N and M, indicates that very likely, there was one particularly major prehistoric migration of humans out of Africa, and both N and M were part of the same colonization process. ==Origins== There is widespread agreement in the scientific community concerning the African ancestry of haplogroup L3 (haplogroup N's parent clade). However, whether or not the mutations which define haplogroup N itself first occurred within Asia or Africa has been a subject for ongoing discussion and study.〔 The out of Africa hypothesis has gained generalized consensus. However, many specific questions remain unsettled. To know whether the two M and N macrohaplogroups that colonized Eurasia were already present in Africa before the exit is puzzling. Torroni et al. 2006 state that Haplogroups M, N and R occurred somewhere between East Africa and the Persian Gulf. Also related to the origins of haplogroup N is whether ancestral haplogroups M, N and R were part of the same migration out of Africa, or whether Haplogroup N left Africa via the Northern route through the Levant, and M left Africa via Horn of Africa. This theory was suggested because haplogroup N is by far the predominant haplogroup in Western Eurasia, and haplogroup M is absent in Western Eurasia, but is predominant in India and is common in regions East of India. However, the mitochondrial DNA variation in isolated "relict" populations in southeast Asia and among Indigenous Australians supports the view that there was only a single dispersal from Africa. Southeast Asian populations and Indigenous Australians all possess deep rooted clades of both haplogroups M and N.〔 The distribution of the earliest branches within haplogroups M, N, and R across Eurasia and Oceania therefore supports a three-founder-mtDNA scenario and a single migration route out of Africa. These findings also highlight the importance of Indian subcontinent in the early genetic history of human settlement and expansion. 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 N (mtDNA)」の詳細全文を読む スポンサード リンク
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