Haplogroup N is a human mitochondrial DNA (mtDNA) clade. A macrohaplogroup, its descendant lineages are distributed across many continents. Like its sibling macrohaplogroup M, macrohaplogroup N is a descendant of the 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 maternal haplogroups that define the theory of the recent African origin of modern humans and subsequent early human migrations around the world. The global distribution of haplogroups N and M indicates that there was likely at least one major prehistoric migration of humans out of Africa, with both N and M later evolving outside the continent.[5]
Origins
There is widespread agreement in the scientific community concerning the African ancestry of haplogroup L3 (haplogroup N's parent clade).[10] 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.[10]
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.[11]
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.[12] 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.[13] These findings also highlight the importance of Indian subcontinent in the early genetic history of human settlement and expansion.[14]
Asian origin hypothesis
The hypothesis of Asia as the place of origin of haplogroup N is supported by the following:
Haplogroup N is found in all parts of the world but has low frequencies in Sub-Saharan Africa. According to a number of studies, the presence of Haplogroup N in Africa is most likely the result of back migration from Eurasia.[4]
The oldest clades of macrohaplogroup N are found in Asia and Australia.
It would be paradoxical that haplogroup N had traveled all the distance to Australia or New World yet failed to affect other populations within Africa besides North Africans and Horn Africans.
N1 is the only sub-clade of haplogroup N that has been observed in Africa. However N1a is the only one in East Africa: this haplogroup is even younger and is not restricted to Africa, N1a has also been detected in Southern Siberia and was found in a 2,500-year-old Scytho-Siberian burial in the Altai region.[15]
The mitochondrial DNA variation in isolated "relict" populations in southeast Asia supports the view that there was only a single dispersal from Africa.[12] The distribution of the earliest branches within haplogroups M, N, and R across Eurasia and Oceania provides additional evidence for a three-founder-mtDNA scenario and a single migration route out of Africa.[13] These findings also highlight the importance of Indian subcontinent in the early genetic history of human settlement and expansion.[14] Therefore, N’s history is similar to M and R which have their most probably origin in South Asia.
African origin hypothesis
According to Toomas Kivisild "the lack of L3 lineages other than M and N in India and among non-African mitochondria in general suggests that the earliest migration(s) of modern humans already carried these two mtDNA ancestors, via a departure route over the Horn of Africa.[7]
Distribution
Haplogroup N is derived from the ancestral L3 macrohaplogroup, which represents the migration discussed in the theory of the recent African origin of modern humans. Haplogroup N is the ancestral haplogroup to almost all clades today distributed in Europe and Oceania, as well as many found in Asia and the Americas. It is believed to have arisen at a similar time to haplogroup M. Haplogroup N subclades like haplogroup U6 are also found at high to low frequencies in northwest and northeast Africa due to a back migration from Europe or Asia during the Paleolithic ca. 46,000 ybp, the estimated age of the basal U6* clade.[16]
The N1 subclade has also been found in various fossils that were analysed for ancient DNA, including specimens associated with the Starčevo (N1a1a1, Alsónyék-Bátaszék, Mérnöki telep, 1/3 or 33%), Linearbandkeramik (N1a1a1a3, Szemely-Hegyes, 1/1 or 100%; N1a1b/N1a1a3/N1a1a1a2/N1a1a1/N1a1a1a, Halberstadt-Sonntagsfeld, 6/22 or ~27%), Alföld Linear Pottery (N1a1a1, Hejőkürt-Lidl, 1/2 or 50%), Transdanubian Late Neolithic (N1a1a1a, Apc-Berekalja, 1/1 or 100%), Protoboleráz (N1a1a1a3, Abony, Turjányos-dűlő, 1/4 or 25%), and Iberia Early Neolithic cultures (N1a1a1, Els Trocs, 1/4 or 25%).[20]
In popular science
In the book The Real Eve, Stephen Oppenheimer refers to haplogroup N as "Nasreen" as haplogroup N may have arisen near the Persian Gulf. In his popular book The Seven Daughters of Eve, Bryan Sykes named the originator of this mtDNA haplogroup "Naomi".
Subgroups distribution
Haplogroup N's derived clades include the macro-haplogroup R and its descendants, and haplogroups A, I, S, W, X, and Y.
Basal N* now occurs at its highest frequencies among the Soqotri (24.3%).[22]
Undifferentiated haplogroup N is especially common in the Horn of Africa, constituting around 20% of maternal lineages among Somalis.[23] It is also found at low frequencies among Algerians and ReguibateSahrawi.[24]
Haplogroup X[41] – found most often in Western Eurasia, but also present in the Americas.[25]
Haplogroup X1 – found primarily in North Africa as well as in some populations of the Levant, notably among the Druze
Haplogroup X2 – found in Western Eurasia, Siberia and among Native Americans
Haplogroup R[42] – a very extended and diversified macro-haplogroup.
Additionally, there are some unnamed N* lineages in South Asia, among indigenous Australians and the Ket people of central Siberia.[25]
Subclades
Tree
This phylogenetic tree of haplogroup N subclades is based on the paper by Mannis van Oven and Manfred Kayser Updated comprehensive phylogenetic tree of global human mitochondrial DNA variation[9] and subsequent published research.
^MacAulay, V.; Hill, C; Achilli, A; Rengo, C; Clarke, D; Meehan, W; Blackburn, J; Semino, O; et al. (2005). "Single, Rapid Coastal Settlement of Asia Revealed by Analysis of Complete Mitochondrial Genomes". Science. 308 (5724): 1034–36. Bibcode:2005Sci...308.1034M. doi:10.1126/science.1109792. PMID15890885. Haplogroup L3 (the African clade that gave rise to the two basal non-African clades, haplogroups M and N) is 84,000 years old, and haplogroups M and N themselves are almost identical in age at 63,000 years old, with haplogroup R diverging rapidly within haplogroup N 60,000 years ago.
^Richards, Martin; Bandelt, Hans-JüRgen; Kivisild, Toomas; Oppenheimer, Stephen (2006). "Human Mitochondrial DNA and the Evolution of Homo sapiens". Nucleic Acids and Molecular Biology. 18: 225–65. doi:10.1007/3-540-31789-9_10. ISBN978-3-540-31788-3. subclades. L3b d, L3e and L3f, for instance, are clearly of African origin, whereas haplogroup N is of apparently Eurasian origin((cite journal)): |chapter= ignored (help); Cite journal requires |journal= (help)
^ abGonder, M. K.; Mortensen, H. M.; Reed, F. A.; De Sousa, A.; Tishkoff, S. A. (2006). "Whole-mtDNA Genome Sequence Analysis of Ancient African Lineages". Molecular Biology and Evolution. 24 (3): 757–68. doi:10.1093/molbev/msl209. PMID17194802.
^ abOlivieri, A.; Achilli, A.; Pala, M.; Battaglia, V.; Fornarino, S.; Al-Zahery, N.; Scozzari, R.; Cruciani, F.; Behar, D. M.; Dugoujon, J.-M.; Coudray, C.; Santachiara-Benerecetti, A. S.; Semino, O.; Bandelt, H.-J.; Torroni, A. (2006). "The mtDNA Legacy of the Levantine Early Upper Palaeolithic in Africa". Science. 314 (5806): 1767–70. Bibcode:2006Sci...314.1767O. doi:10.1126/science.1135566. PMID17170302. The scenario of a back-migration into Africa is supported by another feature of the mtDNA phylogeny. Haplogroup M's Eurasian sister clade, haplogroup N, which has a very similar age to M and no indication of an African origin
^Kivisild; et al. (2007). "Genetic Evidence of Modern Human Dispersals in South Asia". The Evolution and History of Human Populations in South Asia. ((cite book)): External link in |chapterurl= (help); Unknown parameter |chapterurl= ignored (|chapter-url= suggested) (help)
^ abvan Oven M, Kayser M (2009). "Updated comprehensive phylogenetic tree of global human mitochondrial DNA variation". Human Mutation. 30 (2): E386–94. doi:10.1002/humu.20921. PMID18853457.
^Torroni, A; Achilli, A; MacAulay, V; Richards, M; Bandelt, H (2006). "Harvesting the fruit of the human mtDNA tree". Trends in Genetics. 22 (6): 339–45. doi:10.1016/j.tig.2006.04.001. PMID16678300.
^ abMacAulay, V.; Hill, C; Achilli, A; Rengo, C; Clarke, D; Meehan, W; Blackburn, J; Semino, O; et al. (2005). "Single, Rapid Coastal Settlement of Asia Revealed by Analysis of Complete Mitochondrial Genomes". Science. 308 (5724): 1034–36. Bibcode:2005Sci...308.1034M. doi:10.1126/science.1109792. PMID15890885.
^ abIosif Lazaridis; et al. (2016). "The genetic structure of the world's first farmers". bioRxiv059311. ((cite bioRxiv)): Check |biorxiv= value (help)
^ abSebastian Lippold, Hongyang Xu, Albert Ko, Anne Butthof, Mingkun Li, Gabriel Renaud, Roland Schröder, and Mark Stoneking, "Human paternal and maternal demographic histories: insights from high-resolution Y chromosome and mtDNA sequences." bioRxiv posted online January 13, 2014. doi:10.1101/001792
^Hill, C.; Soares, P.; Mormina, M.; MacAulay, V.; Meehan, W.; Blackburn, J.; Clarke, D.; Raja, J. M.; Ismail, P.; Bulbeck, D.; Oppenheimer, S.; Richards, M. (2006). "Phylogeography and Ethnogenesis of Aboriginal Southeast Asians". Molecular Biology and Evolution. 23 (12): 2480–91. doi:10.1093/molbev/msl124. PMID16982817.
^Adrien Rieux, Anders Eriksson, Mingkun Li et al., "Improved Calibration of the Human Mitochondrial Clock Using Ancient Genomes." Mol Biol Evol (2014) doi:10.1093/molbev/msu222