Haplogroup M (mtDNA)


Haplogroup M is a human mitochondrial DNA haplogroup. An enormous haplogroup spanning all the continents, the macro-haplogroup M, like its sibling the macro-haplogroup N, is a descendant of the haplogroup L3.
All mtDNA haplogroups considered native outside of Africa are descendants of either haplogroup M or its sibling haplogroup N. Haplogroup M is relatively young, having a younger most recent common ancestor date than some subclades of haplogroup N such as haplogroup R.

Origins

There is a debate concerning the geographical origins of Haplogroup M and its sibling haplogroup N. Both lineages are thought to have been the main surviving lineages involved in the out of Africa migration because all indigenous lineages found outside Africa belong to haplogroup M or haplogroup N. Scientists are unsure whether the mutations that define haplogroups M and N occurred in Africa before the exit from Africa or in Asia after the exit from Africa. Determining the origins of haplogroup M is further complicated by an early back-migration of bearers of M1.
Its date of origin in absolute terms is only known with great uncertainty, as reconstruction has yielded different ranges for the age of M in South Asia and East Asia. Soares et al. give 95% CI ranges of and for South and East Asia, respectively. The same authors give an estimate for the age of L3 as, later narrowed to the somewhat younger. Thus, haplogroup M would have emerged around 10,000 or at most 20,000 years after L3, around or somewhat after the recent out-of-Africa migration event.

Haplogroup M1

Much discussion concerning the origins of haplogroup M has been related to its subclade haplogroup M1, which is the only variant of macro-haplogroup M found in Africa. Two possibilities were being considered as potential explanations for the presence of M1 in Africa:
  1. M was present in the ancient population which later gave rise to both M1 in Africa, and M more generally found in Eurasia.
  2. The presence of M1 in Africa is the result of a back-migration from Asia which occurred sometime after the Out of Africa migration.

    Haplogroup M23

In 2009, two independent publications reported a rare, deep-rooted subclade of haplogroup M, referred to as M23, that is present in Madagascar.
The contemporary populations of Madagascar were formed in the last 2,000 years by the admixture of Bantu and Indonesian populations. M23 seems to be restricted to Madagascar, as it has not been detected anywhere else. M23 could have been brought to Madagascar from Asia where most deep rooted subclades of Haplogroup M are found.

Asian origin hypothesis

According to this theory, anatomically modern humans carrying ancestral haplogroup L3 lineages were involved in the Out of Africa migration from East Africa into Asia. Somewhere in Asia, the ancestral L3 lineages gave rise to haplogroups M and N. The ancestral L3 lineages were then lost by genetic drift as they are infrequent outside Africa. The hypothesis that Asia is the origin of macrohaplogroup M is supported by the following:
  1. The highest frequencies worldwide of macrohaplogroup M are observed in Asia, specifically in Bangladesh, China, India, Japan, Korea, and Nepal where frequencies range from 60 to 80%. The total frequency of M subclades is even higher in some populations of Siberia or the Americas, but these small populations tend to exhibit strong genetic drift effects, and often their geographical neighbors exhibit very different frequencies.
  2. Deep time depth >50,000 years of western, central, southern and eastern Indian haplogroups M2, M38, M54, M58, M33, M6, M61, M62 and the distribution of macrohaplogroup M, do not rule out the possibility of macrohaplogroup M arising in Indian population.
  3. With the exception of the African specific M1, India has several M lineages that emerged directly from the root of haplogroup M.
  4. Only two subclades of haplogroup M, M1 and M23, are found in Africa, whereas numerous subclades are found outside Africa.
  5. Specifically concerning M1

    African origin hypothesis

According to this theory, haplogroups M and N arose from L3 in an East African population ancestral to eurasians that had been isolated from other African populations before the OOA event. Members of this population were involved in the out Africa migration and may have only carried M and N lineages. With the possible exception of haplogroup M1, all other M and N clades in Africa were lost due to admixture with other African populations and genetic drift.
The African origin of Haplogroup M is supported by the following arguments and evidence.
  1. L3, the parent clade of haplogroup M, is found throughout Africa, but is rare outside Africa. 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 of modern humans already carried these two mtDNA ancestors, via a departure route over the Horn of Africa."
  2. Specifically concerning at least M1:

    Dispersal

A number of studies have proposed that the ancestors of modern haplogroup M dispersed from Africa through the southern route across the Horn of Africa along the coastal regions of Asia onwards to New Guinea and Australia. These studies suggested that the migrations of haplogroups M and N occurred separately with haplogroup N heading northwards from East Africa to the Levant. However, the results of numerous recent studies indicate that there was only one migration out of Africa and that haplogroups M and N were part of the same migration. This is based on the analysis of a number of relict populations along the proposed beachcombing route from Africa to Australia, all of which possessed both haplogroups N and M.
A 2008 study by Abu-Amero et al., suggests that the Arabian Peninsula may have been the main route out of Africa. However, as the region lacks of autochthonous clades of haplogroups M and N the authors suggest that the area has been a more recent receptor of human migrations than an ancient demographic expansion center along the southern coastal route as proposed under the single migration Out-of-Africa scenario of the African origin hypothesis.

Distribution

M is the most common mtDNA haplogroup in Asia, super-haplogroup M is distributed all over Asia, where it represents 60% of all maternal lineages.
All Andamanese subgroups of M which is unique to Andamanese people. It peaks in the Malaysian aboriginal Negrito tribes of Semang; 84% in Mendriq people, Batek people 48%, It also peaks very high in Japan and Tibet, where it represents on average about 70% of the maternal lineages and is ubiquitous in India and South Korea, where it has approximately 60% frequency. Among Chinese people both inside and outside of China, haplogroup M accounts for approximately 50% of all mtDNA on average, but the frequency varies from approximately 40% in Hans from Hunan and Fujian in southern China to approximately 60% in Shenyang, Liaoning in northeastern China.
Haplogroup M accounts for approximately 42% of all mtDNA in Filipinos, among whom it is represented mainly by M7c3c and E. In Vietnam, haplogroup M has been found in 37% to 48% of samples of Vietnamese and in 32% of a sample of Chams from Bình Thuận Province. Haplogroup M accounts for 43% of all mtDNA in a sample of Laotians, with its subclade M7 alone accounting for a full third of all haplogroup M, or 14.5% of the total sample.
In Oceania, A 2008 study found Haplogroup M in 42% of a pool of samples from nine language groups in the Admiralty Islands of Papua New Guinea., M has been found in 35% of a sample of Papua New Guinea highlanders from the Bundi area and in 28% of a sample of Aboriginal Australians from Kalumburu in northwestern Australia. In a study published in 2015, Haplogroup M was found in 21% of a sample of Fijians, but it was not observed in a sample of 21 Rotumans.
Haplogroup M is also relatively common in Northeast Africa, occurring especially among Somalis, Libyans and Oromos at frequencies over 20%. Toward the northwest, the lineage is found at comparable frequencies among the Tuareg in Mali and Burkina Faso; particularly the M1a2 subclade.
Among the descendant lineages of haplogroup M are C, D, E, G, Q, and Z. Z and G are found in North Eurasian populations, C and D exists among North Eurasian and Native American populations, E is observed in Southeast Asian populations, and Q is common among Melanesian populations. The lineages M2, M3, M4, M5, M6, M18 and M25 are exclusive to South Asia, with M2 reported to be the oldest lineage on the Indian sub-continent.
In 2013, four ancient specimens dated to around 2,500 BC-500 AD, which were excavated from the Tell Ashara and Tell Masaikh archaeological sites in the Euphrates Valley, were found to belong to mtDNA haplotypes associated with the M4b1, M49 and/or M61 haplogroups. Since these clades are not found among the current inhabitants of the area, they are believed to have been brought at a more remote period from east of Mesopotamia; possibly by either merchants or the founders of the ancient Terqa population.
In 2016, three Late Pleistocene European hunter-gatherers were also found to carry M lineages. Two of the specimens were from the Goyet archaeological site in Belgium and were dated to 34,000 and 35,000 years ago, respectively. The other ancient individual hailed from the La Rochette site in France, and was dated to 28,000 years ago.
Ancient DNA analysis of Iberomaurusian skeletal remains at the Taforalt site in Morocco, which have been dated to between 15,100 and 13,900 ybp, observed the M1b subclade in one of the fossils. Ancient individuals belonging to the Late Iron Age settlement of Çemialo Sırtı in Batman, southeast Turkey were found to carry haplogroup M; specifically the M1a1 subclade. Haplogroup M was also detected in ancient specimens from Southeast Anatolia. Additionally, M1 has been observed among ancient Egyptian mummies excavated at the Abusir el-Meleq archaeological site in Middle Egypt, which date from the Pre-Ptolemaic/late New Kingdom and Roman periods. Fossils at the Early Neolithic site of Ifri n'Amr or Moussa in Morocco, which have been dated to around 5,000 BCE, have also been found to carry the M1b subclade. These ancient individuals bore an autochthonous Maghrebi genomic component that peaks among modern Berbers, indicating that they were ancestral to populations in the area. The ancient Egyptian aristocrats Nakht-Ankh and Khnum-Nakht were also found to belong to the M1a1 subclade. The half-brothers lived during the 12th Dynasty, with their tomb located at the Deir Rifeh cemetery in Middle Egypt.

Subgroups distribution

Tree

This phylogenetic tree of haplogroup M subclades is based on the paper by Mannis van Oven and Manfred Kayser Updated comprehensive phylogenetic tree of global human mitochondrial DNA variation and subsequent published research.