Haplogroup X diverged from
haplogroup N, roughly 30,000 years ago (just prior to or during the
Last Glacial Maximum). It is in turn ancestral to subclades X2 and X1, which arose
c.16-21 thousand and
c.14-24 thousand years ago, respectively.[1]
Distribution
Haplogroup X is found in approximately 2% of
native Europeans,[4] and 13% of all native North Americans.[5][6] Additionally, the Haplogroup is present in around 3% of Assyrians, with high concentrations in
Erzurum, Turkey as well.[citation needed] Notably, the haplogroup is especially common, at 14.3%, among the natives of
Bahariya Oasis (
Western Desert, Egypt.[7] The X1 subclade is much less frequent, and is largely restricted to North Africa, the
Horn of Africa and the Near East.
Subclade X2 appears to have undergone extensive population expansion and dispersal around or soon after the
Last Glacial Maximum, roughly 20,000 years ago. It is more strongly represented in the Near East, the
Caucasus, and southern Europe, and somewhat less strongly present in the rest of Europe. The highest concentrations are found in the
Ojibwe (25%),
Sioux (15%),
Nuu-Chah-Nulth (12%),
Georgia (8%),
Orkney (7%), and amongst the
DruzeAssyrian community in Israel (27%). Subclades of X2 are not present in South Americans Amerindian populations.[8]The oldest known human associated with X2 is
Kennewick Man,[citation needed] whose
c. 9000-year old remains were discovered in
Washington State.
Archaeogenetics
Haplogroup X has been found in various other bone specimens that were analysed for ancient DNA, including specimens associated with the
AlföldLinear Pottery (X2b-T226C, Garadna-Elkerülő út site 2, 1/1 or 100%),
Linearbandkeramik (X2d1, Halberstadt-Sonntagsfeld, 1/22 or ~5%), and
Iberia Chalcolithic (X2b, La Chabola de la Hechicera, 1/3 or 33%; X2b, El Sotillo, 1/3 or 33%; X2b, El Mirador Cave, 1/12 or ~8%) cultures.[9]Abel-beth-maachah 2201 was a man who lived between 1014 and 836 BC during the
LevantIron Age and was found in the region now known as Abel Beth Maacah,
Metula, Israel. He was associated with the
Galilean cultural group. His direct maternal line belonged to mtDNA haplogroup X2b. Haplogroup X has been found in ancient Assyria and ancient Egyptian mummies excavated at the
Abusir el-Meleq archaeological site in Middle Egypt, which date from the late
New Kingdom and
Roman periods.[10] Fossils excavated at the Late Neolithic site of
Kelif el Boroud in
Morocco, which have been dated to around 5,000 years old, have also been found to carry the X2 subclade.[11]
Druze
In Eurasia, the greatest frequency of haplogroup X is observed in the
Druze, a minority population in
Israel,
Jordan,
Lebanon, and
Syria, as much in X1 (16%) as in X2 (11%).[12] The Druze also have much diversity of X lineages. This pattern of heterogeneous parental origins is consistent with Druze oral tradition. The
Galilee Druze represent a population isolate, so their combination of a high frequency and diversity of X signifies a phylogenetic refugium, providing a sample snapshot of the genetic landscape of the Near East prior to the modern age.[13]
Although it occurs only at a frequency of about 3% for the total current indigenous population of the Americas, it is a bigger haplogroup in northern North America, where among the
Algonquian peoples it comprises up to 25% of mtDNA types.[15][16] It is also present in lesser percentages to the west and south of this area—among the
Sioux (15%), the
Nuu-chah-nulth (11%–13%), the
Navajo (7%), and the
Yakama (5%).[17][18] In Latin America, Haplotype X6 was present in the
Tarahumara 1.8% (1/53) and
Huichol 20% (3/15)[19] X6 and X7 was also found in 12% in
Yanomani people.[20]
Unlike the four main Native American mtDNA haplogroups (
A,
B,
C,
D), X is not strongly associated with
East Asia. The main occurrence of X in Asia discovered so far is in the
Altai people in
Siberia.[21]
One theory of how the X Haplogroup ended up in North America is that the people carrying it migrated from central Asia along with haplogroups A, B, C, and D, from an ancestor from the
Altai Region of Central Asia.[12] Two sequences of haplogroup X2 were sampled further east of Altai among the
Evenks of Central Siberia.[12] These two sequences belong to X2* and X2b. It is uncertain if they represent a remnant of the migration of X2 through Siberia or a more recent input.[12]
This relative absence of haplogroup X2 in Asia is one of the major factors used to support the
Solutrean hypothesis during the early 2000s.
The Solutrean hypothesis postulates that haplogroup X reached North America with a wave of European migration emerging from the
Solutrean culture, a stone-age culture in south-western
France and in
Spain, by boat around the southern edge of the
Arctic ice pack roughly 20,000 years ago.[22][23]
Since the later 2000s and during the 2010s, evidence has turned against the Solutrean hypothesis, as no presence of mt-DNA ancestral to X2a has been found in Europe or the Near East. New World lineages X2a and X2g are not derived from the Old World lineages X2b, X2c, X2d, X2e, and X2f, indicating an early origin of the New World lineages "likely at the very beginning of their expansion and spread from the Near East".[12]
A 2008 study came to the conclusion that the presence of haplogroup X in the Americas does not support migration from Solutrean-period Europe.[17]
The lineage of haplogroup X in the Americas is not derived from a European subclade, but rather represent an independent subclade, labelled X2a.[24]
The X2a subclade has not been found in Eurasia, and has most likely arisen within the early Paleo-Indian population, at roughly 13,000 years ago.[25] A basal variant of X2a was found in the
Kennewick Man fossil (ca. 9,000 years ago).[26]
Subclades
Tree
This phylogenetic tree of haplogroup X subclades is based on the paper by Mannis van Oven and Manfred Kayser Updated comprehensive phylogenetic tree of global human mitochondrial DNA variation[3] and subsequent published research.
^Malhi, Ripan S.; Smith, David Glenn (September 2002). "Brief communication: Haplogroup X confirmed in prehistoric North America". American Journal of Physical Anthropology. 119 (1): 84–86.
doi:
10.1002/ajpa.10106.
hdl:2027.42/34275.
PMID12209576.
^Kujanová, Martina; Pereira, Luísa; Fernandes, Verónica; Pereira, Joana B.; Černý, Viktor (October 2009). "Near Eastern Neolithic genetic input in a small oasis of the Egyptian Western Desert". American Journal of Physical Anthropology. 140 (2): 336–346.
doi:
10.1002/ajpa.21078.
PMID19425100.
^"Learn about Y-DNA Haplogroup Q". Wendy Tymchuk – Senior Technical Editor. Genebase Systems. 2008. Archived from
the original(Verbal tutorial possible) on 22 June 2010. Retrieved 21 November 2009.
^Bradley, Bruce; Stanford, Dennis (December 2004). "The North Atlantic ice-edge corridor: A possible Palaeolithic route to the New World". World Archaeology. 36 (4): 459–478.
doi:
10.1080/0043824042000303656.
S2CID161534521.
^
"The similarities in ages and geographical distributions for C4c and the previously analyzed X2a lineage provide support to the scenario of a dual origin for Paleo-Indians. Taking into account that C4c is deeply rooted in the Asian portion of the mtDNA phylogeny and is indubitably of Asian origin, the finding that C4c and X2a are characterized by parallel genetic histories definitively dismisses the controversial hypothesis of an Atlantic glacial entry route into North America. Hooshiar Kashani B, Perego UA, Olivieri A, Angerhofer N, Gandini F, Carossa V, Lancioni H, Semino O, Woodward SR, Achilli A, Torroni A (January 2012). "Mitochondrial haplogroup C4c: a rare lineage entering America through the ice-free corridor?". American Journal of Physical Anthropology. 147 (1): 35–39.
doi:
10.1002/ajpa.21614.
PMID22024980.
^X2a is dated 12.8+7.1 −6.7 kya in Soares et al. (2009).
^"X2a has not been found anywhere in Eurasia, and phylogeography gives us no compelling reason to think it is more likely to come from Europe than from Siberia. Furthermore, analysis of the complete genome of Kennewick Man, who belongs to the most basal lineage of X2a yet identified, gives no indication of recent European ancestry and moves the location of the deepest branch of X2a to the West Coast, consistent with X2a belonging to the same ancestral population as the other founder mitochondrial haplogroups. Nor have any high-resolution studies of genome-wide data from Native American populations yielded any evidence of Pleistocene European ancestry or trans-Atlantic gene flow."
Raff, Jennifer A.; Bolnick, Deborah A (2015).
"Does Mitochondrial Haplogroup X Indicate Ancient Trans-Atlantic Migration to the Americas? A Critical Re-Evaluation". PaleoAmerica. 1 (4): 297–304.
doi:10.1179/2055556315Z.00000000040.
^Heine, Steven J. (2017). DNA Is Not Destiny: The Remarkable, Completely Misunderstood Relationship between You and Your Genes. W.W. Norton.
Ribetio-dos-Santos AK, Santos SE, Machado AL, Guapindaia V, Zago MA (September 1996). "Heterogeneity of mitochondrial DNA haplotypes in Pre-Columbian Natives of the Amazon region". American Journal of Physical Anthropology. 101 (1): 29–37.
doi:
10.1002/(SICI)1096-8644(199609)101:1<29::AID-AJPA3>3.0.CO;2-8.
PMID8876812.
Zakharov IA, Derenko MV, Maliarchuk BA, Dambueva IK, Dorzhu CM, Rychkov SY (April 2004). "Mitochondrial DNA variation in the aboriginal populations of the Altai-Baikal region: implications for the genetic history of North Asia and America". Annals of the New York Academy of Sciences. 1011 (1): 21–35.
Bibcode:
2004NYASA1011...21Z.
doi:
10.1196/annals.1293.003.
PMID15126280.
S2CID37139929.