Haplogroup A (Y-DNA)
This article needs to be updated.March 2013)(
Haplogroup A also known as A-V148 and A-CTS2809/L991 is a human Y-chromosome DNA haplogroup. It is the foundational haplogroup to all known patrilineal lineages carried by modern humans, and thus is the Y-chromosomal Adam.
|Possible time of origin||roughly 270,000 years ago or about 275,000 years ago (303-241,000 years ago) or 291,000 years ago|
|Coalescence age||235,900 ybp|
|Possible place of origin||Africa|
|Ancestor||Human Y-MRCA (A00-T)|
|Descendants||primary: A00 (AF6/L1284), A0-T |
(Subclades of these include haplogroups A0, A1, A1a, A1b, A1b1 and BT.)
|Highest frequencies||macro-haplogroup subclades found among various populations in Northwest-Central Africa|
Formerly also known as "clade I", bearers of extant sub-clades of haplogroup A are entirely found in Africa (or among descendants of recently moved African populations), in contrast with the descendant haplogroup BT (clade II-X) bearers of which participated in the Out of Africa migration of anatomically modern humans.
The most basal subclades of haplogroup A are, by age of divergence, "A00", "A0", "A1" (also "A1a-T") and "A2-T". Haplogroup BT, which is ancestral to all non-African haplogroups, is a subclade of A2-T.
- 1 Origin
- 2 Distribution
- 3 Structure & subclade distribution
- 4 Nomenclature & taxonomical history
- 5 See also
- 6 References
- 7 External links
There are terminological difficulties,[clarification needed] but as "haplogroup A" has come to mean "the foundational haplogroup" (viz. of contemporary human population), haplogroup A is not defined by any mutation but refers to any haplogroup which is not descended from the haplogroup BT, i.e. defined by the absence of the defining mutation of that group (M91). By this definition, haplogroup A includes all mutations that took place between the Y-MRCA (estimated at some 270 kya) and the mutation defining haplogroup BT (estimated at some 80–70 kya), including any extant subclades that may yet to be discovered.
Bearers of haplogroup A (i.e. absence of the defining mutation of haplogroup BT) have been found in Southern Africa's hunter-gatherer inhabited areas, especially among the San people. In addition, the most basal mitochondrial DNA lineages are also largely restricted to the San. However, the A lineages of Southern Africa are sub-clades of A lineages found in other parts of Africa, suggesting that A sub-haplogroups arrived in Southern Africa from elsewhere.
The two most basal lineages of haplogroup A, A0 and A1 (prior to the announcement of the discovery of haplogroup A00 in 2013), have been detected in West Africa, Northwest Africa and Central Africa. Cruciani et al. (2011) suggest that these lineages may have emerged somewhere in between Central and Northwest Africa. Scozzari et al. (2012) also supported "the hypothesis of an origin in the north-western quadrant of the African continent for the A1b [ i.e. A0 ] haplogroup".
The clade achieves its highest modern frequencies in the Bushmen hunter-gatherer populations of Southern Africa, followed closely by many Nilotic groups in Eastern Africa. However, haplogroup A's oldest sub-clades are exclusively found in Central-Northwest Africa, where it (and by extension the patrilinear ancestor of modern humans) is believed to have originated. Estimates of its time depth have varied greatly, at either close to 190 kya or close to 140 kya in separate 2013 studies, and with the inclusion of the previously unknown "A00" haplogroup to about 270 kya in 2015 studies.
The clade has also been observed at notable frequencies in certain populations in Ethiopia, as well as some Pygmy groups in Central Africa, and less commonly Niger–Congo speakers, who largely belong to the E1b1a clade. Haplogroup E in general is believed to have originated in Northeast Africa, and was later introduced to West Africa from where it spread around 5,000 years ago to Central, Southern and Southeastern Africa with the Bantu expansion. According to Wood et al. (2005) and Rosa et al. (2007), such relatively recent population movements from West Africa changed the pre-existing population Y chromosomal diversity in Central, Southern and Southeastern Africa, replacing the previous haplogroups in these areas with the now dominant E1b1a lineages. Traces of ancestral inhabitants, however, can be observed today in these regions via the presence of the Y DNA haplogroups A-M91 and B-M60 that are common in certain relict populations, such as the Mbuti Pygmies and the Khoisan.
|||Tsumkwe San (Namibia)||66%|
|||Khwe (South Africa)||12|
|||South Semitic (Ethiopia)||10|
In a composite sample of 3551 African men, Haplogroup A had a frequency of 5.4%. The highest frequencies of haplogroup A have been reported among the Khoisan of Southern Africa, Beta Israel, and Nilo-Saharans from Sudan.
African Great LakesEdit
Bantus in Kenya (14%, Luis et al. 2004) and Iraqw in Tanzania (3/43 = 7.0% (Luis et al. 2004) to 1/6 = 17% (Knight et al. 2003)).
Haplogroup A3b2-M13 has been observed in populations of northern Cameroon (2/9 = 22% Tupuri, 4/28 = 14% Mandara, 2/17 = 12% Fulbe) and eastern DRC (2/9 = 22% Alur, 1/18 = 6% Hema, 1/47 = 2% Mbuti).
Without testing for any subclade, haplogroup A Y-DNA has been observed in samples of several populations of Gabon, including 9% (3/33) of a sample of Baka, 3% (1/36) of a sample of Ndumu, 2% (1/46) of a sample of Duma, 2% (1/57) of a sample of Nzebi, and 2% (1/60) of a sample of Tsogo.
Horn of AfricaEdit
Haplogroup A is found at low to moderate frequencies in the Horn of Africa. The clade is observed at highest frequencies among the 41% of a sample of the Beta Israel, occurring among 41% of one sample from this population (Cruciani et al. 2002). Elsewhere in the region, haplogroup A has been reported in 14.6% (7/48) of an Amhara sample, 10.3% (8/78) of an Oromo sample, and 13.6% (12/88) of another sample from Ethiopia.
In the Tamazgha, haplogroup is largely absent. Its subclade A1 has been observed at trace frequencies among Moroccans.
Haplogroup A3b2-M13 is common among the Southern Sudanese (53%), especially the Dinka Sudanese (61.5%). Haplogroup A3b2-M13 also has been observed in another sample of a South Sudanese population at a frequency of 45% (18/40), including 1/40 A3b2a-M171.
Further downstream around the Nile valley, the subclade A3b2 has also been observed at very low frequencies in a sample of Egyptian males (3%).
One 2005 study has found haplogroup A in samples of various Khoisan-speaking tribes with frequency ranging from 10% to 70%. This particular haplogroup was not found in a sample of the Hadzabe from Tanzania, a population sometimes proposed as a remnant of a Late Stone Age Khoisanid population.
In Asia, haplogroup A has been observed at low frequencies in Asia Minor and the Middle East among Aegean Turks, Palestinians, Jordanians, Yemenites.
Haplogroup A1a (A-M31) appears to have present among a very small number of phenotypically northern European males since pre-modern times – the best documented example are men with the surname Revis, which originated in Yorkshire, England.
A3a2 (A-M13; formerly A3b2), has been observed at very low frequencies in some Mediterranean islands. Without testing for any subclade, haplogroup A has been found in a sample of Greeks from Mitilini on the Aegean island of Lesvos and in samples of Portuguese from southern Portugal, central Portugal, and Madeira. The authors of one study have reported finding what appears to be haplogroup A in 3.1% (2/65) of a sample of Cypriots, though they have not definitively excluded the possibility that either of these individuals may belong to a rare subclade of haplogroup BT, including haplogroup CT.
Structure & subclade distributionEdit
- A00a (L1149, FGC25576, FGC26292, FGC26293, FGC27741)
- A00b (A4987/YP3666, A4981, A4982/YP2683, A4984/YP2995, A4985/YP3292, A4986, A4988/YP3731)
- A0 (CTS2809/L991) formerly A1b
- A1 (P305) formerly A1a-T, A0 and A1b
- A1a (M31)
- A1b (P108) formerly A2-T
- A1b1 (L419/PF712)
- A1b1a (L602, V50, V82, V198, V224)
- A1b1a1 (M14) formerly A2
- A1b1a1a (M6)
- A1b1a1a1 (P28) formerly A1b1a1a1b and A2b
- A1b1a1a (M6)
- A1b1a1 (M14) formerly A2
- A1b1b (M32) formerly A3
- A1b1b1 (M28) formerly A3a
- A1b1b2 (L427)
- A1b1b2a (M51/Page42) formerly A3b1
- A1b1b2a1 (P291)
- A1b1b2b (M13/PF1374) formerly A3b2
- A1b1b2b1 (M118)
- A1b1b2a (M51/Page42) formerly A3b1
- A1b1a (L602, V50, V82, V198, V224)
- BT (M91)
- A1b1 (L419/PF712)
Mendez et al. (2013) announced the discovery of a previously unknown haplogroup, for which they proposed the designator "A00". It has an estimated age of around 270 kya, so postdates apppearance of anatomically modern humans, such as Jebel Irhoud.
A00 is also sometimes known as "Perry's Y-chromosome" (or simply "Perry's Y"). This previously unknown haplogroup was discovered in 2012, in the Y chromosome of an African-American man, who had submitted his DNA for commercial genealogical analysis.) The subsequent discovery of other males belonging to A00 led to the reclassification of Perry's Y as A00a (A-L1149).
Researchers later found A00 was possessed by 11 Mbo males of Western Cameroon (out of a sample of 174 (6.32%). Subsequent research suggested that the overall rate of A00 was even higher among the Mbo, i.e. 9.3% (8 of 86) were later found to fall within A00b (A-A4987).
Further research in 2015 indicates that the modern population with the highest concentration of A00 is the Bangwa (or Nweh), a Yemba-speaking group of Cameroon (fr:Bangoua (peuple)): 27 of 67 (40.3%) samples were positive for A00a (L1149). One Bangwa individual did not fit into either A00a or A00b.
Geneticists sequenced genome-wide DNA data from four people buried at the site of Shum Laka in Cameroon between 8000–3000 years ago, who were most genetically similar to Mbuti pygmies. One individual carried the deeply divergent Y chromosome haplogroup A00.
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The subclade A1a (M31) has been found in approximately 2.8% (8/282) of a pool of seven samples of various ethnic groups in Guinea-Bissau, especially among the Papel-Manjaco-Mancanha (5/64 = 7.8%). In an earlier study published in 2003, Gonçalves et al. have reported finding A1a-M31 in 5.1% (14/276) of a sample from Guinea-Bissau and in 0.5% (1/201) of a pair of samples from Cabo Verde. The authors of another study have reported finding haplogroup A1a-M31 in 5% (2/39) of a sample of Mandinka from Senegambia and 2% (1/55) of a sample of Dogon from Mali. Haplogroup A1a-M31 also has been found in 3% (2/64) of a sample of Berbers from Morocco and 2.3% (1/44) of a sample of unspecified ethnic affiliation from Mali.
In 2007, seven men from Yorkshire, England sharing the unusual surname Revis were identified as being from the A1a (M31) subclade. It was discovered that these men had a common male-line ancestor from the 18th century, but no previous information about African ancestry was known.
The subclade A1b1a1a (M6; formerly A2 and A1b1a1a-M6) is typically found among Khoisan peoples. The authors of one study have reported finding haplogroup A-M6(xA-P28) in 28% (8/29) of a sample of Tsumkwe San and 16% (5/32) of a sample of !Kung/Sekele, and haplogroup A2b-P28 in 17% (5/29) of a sample of Tsumkwe San, 9% (3/32) of a sample of !Kung/Sekele, 9% (1/11) of a sample of Nama, and 6% (1/18) of a sample of Dama. The authors of another study have reported finding haplogroup A2 in 15.4% (6/39) of a sample of Khoisan males, including 5/39 A2-M6/M14/M23/M29/M49/M71/M135/M141(xA2a-M114) and 1/39 A2a-M114.
The subclade A1b1b1 (M28; formerly A3a) has only been rarely observed in the Horn of Africa. In 5% (1/20) of a mixed sample of speakers of South Semitic languages from Ethiopia, 1.1% (1/88) of a sample of Ethiopians, and 0.5% (1/201) in Somalis.
The subclade A1b1b2a (M51; formerly A3b1) occurs most frequently among Khoisan peoples (6/11 = 55% Nama, 11/39 = 28% Khoisan, 7/32 = 22% !Kung/Sekele, 6/29 = 21% Tsumkwe San, 1/18 = 6% Dama). However, it also has been found with lower frequency among Bantu peoples of Southern Africa, including 2/28 = 7% Sotho–Tswana, 3/53 = 6% non-Khoisan Southern Africans, 4/80 = 5% Xhosa, and 1/29 = 3% Zulu.
The subclade A1b1b2b (M13; formerly A3b2) is primarily distributed among Nilotic populations in East Africa and northern Cameroon. It is different from the A subclades that are found in the Khoisan samples and only remotely related to them (it is actually only one of many subclades within haplogroup A). This finding suggests an ancient divergence.
In Sudan, haplogroup A-M13 has been found in 28/53 = 52.8% of Southern Sudanese, 13/28 = 46.4% of the Nuba of central Sudan, 25/90 = 27.8% of Western Sudanese, 4/32 = 12.5% of local Hausa people, and 5/216 = 2.3% of Northern Sudanese.
In Ethiopia, one study has reported finding haplogroup A-M13 in 14.6% (7/48) of a sample of Amhara and 10.3% (8/78) of a sample of Oromo. Another study has reported finding haplogroup A3b2b-M118 in 6.8% (6/88) and haplogroup A3b2*-M13(xA3b2a-M171, A3b2b-M118) in 5.7% (5/88) of a mixed sample of Ethiopians, amounting to a total of 12.5% (11/88) A3b2-M13.
Haplogroup A-M13 also has been observed occasionally outside of Central and Eastern Africa, as in the Aegean Region of Turkey (2/30 = 6.7%), Yemenite Jews (1/20 = 5%), Egypt (4/147 = 2.7%, 3/92 = 3.3%), Palestinian Arabs (2/143 = 1.4%), Sardinia (1/77 = 1.3%, 1/22 = 4.5%), the capital of Jordan, Amman (1/101=1%), and Oman (1/121 = 0.8%).
Haplogroup A-M13 has been found among three Neolithic period fossils excavated from the Kadruka site in Sudan.
Nomenclature & taxonomical historyEdit
Prior to 2002, there were in academic literature at least seven naming systems for the Y-Chromosome Phylogenetic tree. This led to considerable confusion. In 2002, the major research groups came together and formed the Y-Chromosome Consortium (YCC). They published a joint paper that created a single new tree that all agreed to use. Later, a group of citizen scientists with an interest in population genetics and genetic genealogy formed a working group to create an amateur tree aiming at being above all timely. The table below brings together all of these works at the point of the landmark 2002 YCC Tree. This allows a researcher reviewing older published literature to quickly move between nomenclatures.
Initial sequencing of the human Y-chromosome had suggested that first split in the Y-Chromosome family tree occurred with the mutations that separated Haplogroup BT from Y-chromosomal Adam and haplogroup A more broadly. Subsequently, many intervening splits between Y-chromosomal Adam and BT, also became known.
A major shift in the understanding of the Y-DNA tree came with the publication of (Cruciani 2011). While the SNP marker M91 had been regarded as a key to identifying haplogroup BT, it was realised that the region surrounding M91 was a mutational hotspot, which is prone to recurrent back-mutations. Moreover, the 8T stretch of Haplogroup A represented the ancestral state of M91, and the 9T of haplogroup BT a derived state, which arose following the insertion of 1T. This explained why subclades A1b and A1a, the deepest branches of Haplogroup A, both possessed the 8T stretch. Similarly, the P97 marker, which was also used to identify haplogroup A, possessed the ancestral state in haplogroup A, but a derived state in haplogroup BT. Ultimately the tendency of M91 to back-mutate and (hence) its unreliability, led to M91 being discarded as a defining SNP by ISOGG in 2016. Conversely, P97 has been retained as a defining marker of Haplogroup BT.
|YCC 2002/2008 (Shorthand)||(α)||(β)||(γ)||(δ)||(ε)||(ζ)||(η)||YCC 2002 (Longhand)||YCC 2005 (Longhand)||YCC 2008 (Longhand)||YCC 2010r (Longhand)||ISOGG 2006||ISOGG 2007||ISOGG 2008||ISOGG 2009||ISOGG 2010||ISOGG 2011||ISOGG 2012|
The following research teams per their publications were represented in the creation of the YCC Tree.
- Human Y-chromosome DNA haplogroup
- Y-DNA haplogroups in populations of Sub-Saharan Africa
- Y-DNA haplogroups by ethnic group
- Y-DNA A subclades
- equivalent to an estimate of the age of the human Y-MRCA (see there); including the A00 lineage, Karmin et al. (2015) and Trombetta et al. (2015) estimate ages of 254,000 and 291,000 ybp, respectively.
- Karmin; et al. (2015). "A recent bottleneck of Y chromosome diversity coincides with a global change in culture". Genome Research. 25 (4): 459–66. doi:10.1101/gr.186684.114. PMC 4381518. PMID 25770088. "we date the Y-chromosomal most recent common ancestor (MRCA) in Africa at 254 (95% CI 192–307) kya and detect a cluster of major non-African founder haplogroups in a narrow time interval at 47–52 kya, consistent with a rapid initial colonization model of Eurasia and Oceania after the out-of-Africa bottleneck. In contrast to demographic reconstructions based on mtDNA, we infer a second strong bottleneck in Y-chromosome lineages dating to the last 10 ky. We hypothesize that this bottleneck is caused by cultural changes affecting variance of reproductive success among males."
- Mendez, L.; et al. (2016). "The Divergence of Neandertal and Modern Human Y Chromosomes". The American Journal of Human Genetics. 98 (4): 728–34. doi:10.1016/j.ajhg.2016.02.023. PMC 4833433. PMID 27058445.
- Trombetta, Beniamino; d'Atanasio, Eugenia; Massaia, Andrea; Myres, Natalie M.; Scozzari, Rosaria; Cruciani, Fulvio; Novelletto, Andrea (2015). "Regional Differences in the Accumulation of SNPs on the Male-Specific Portion of the Human Y Chromosome Replicate Autosomal Patterns: Implications for Genetic Dating". PLOS ONE. 10 (7): e0134646. doi:10.1371/journal.pone.0134646. PMC 4520482. PMID 26226630.
- According to Cruciani et al. 2011, the most basal lineages have been detected in West, Northwest and Central Africa, suggesting plausibility for the Y-MRCA living in the general region of North-Central Africa". In a sample of 2204 African Y-chromosomes, 8 chromosomes belonged to either haplogroup A1b or A1a. Haplogroup A1a was identified in two Moroccan Berbers, one Fulbe and one Tuareg people from Niger. Haplogroup A1b was identified in three Bakola pygmies from Southern Cameroon and one Algerian Berber. Cruciani, Fulvio; Trombetta, Beniamino; Massaia, Andrea; Destro-Bisol, Giovanni; Sellitto, Daniele; Scozzari, Rosaria (2011). "A Revised Root for the Human Y Chromosomal Phylogenetic Tree: The Origin of Patrilineal Diversity in Africa". The American Journal of Human Genetics. 88 (6): 814–8. doi:10.1016/j.ajhg.2011.05.002. PMC 3113241. PMID 21601174. Scozzari et al. (2012) agreed with a plausible placement in "the north-western quadrant of the African continent" for the emergence of the A1b haplogroup: "the hypothesis of an origin in the north-western quadrant of the African continent for the A1b haplogroup, and, together with recent findings of ancient Y-lineages in central-western Africa, provide new evidence regarding the geographical origin of human MSY diversity". Scozzari R; Massaia A; D'Atanasio E; Myres NM; Perego UA; et al. (2012). Caramelli, David (ed.). "Molecular Dissection of the Basal Clades in the Human Y Chromosome Phylogenetic Tree". PLOS ONE. 7 (11): e49170. doi:10.1371/journal.pone.0049170. PMC 3492319. PMID 23145109.
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- Scozzari R, Massaia A, D'Atanasio E, et al. (2012). "Molecular dissection of the basal clades in the human Y chromosome phylogenetic tree". PLOS ONE. 7 (11): e49170. doi:10.1371/journal.pone.0049170. PMC 3492319. PMID 23145109.
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- Capelli C, Redhead N, Romano V, et al. (March 2006). "Population structure in the Mediterranean basin: a Y chromosome perspective". Ann. Hum. Genet. 70 (Pt 2): 207–25. doi:10.1111/j.1529-8817.2005.00224.x. hdl:2108/37090. PMID 16626331.
- Krahn, Thomas. "YCC Tree". FTDNA. Archived from the original on 2011-07-26.
- Mendez, Fernando; Krahn, Thomas; Schrack, Bonnie; Krahn, Astrid-Maria; Veeramah, Krishna; Woerner, August; Fomine, Forka Leypey Mathew; Bradman, Neil; Thomas, Mark; Karafet, Tatiana M.; Hammer, Michael F. (7 March 2013). "An African American paternal lineage adds an extremely ancient root to the human Y chromosome phylogenetic tree" (PDF). American Journal of Human Genetics. 92 (3): 454–9. doi:10.1016/j.ajhg.2013.02.002. PMC 3591855. PMID 23453668. "Genotyping of a DNA sample that was submitted to a commercial genetic-testing facility demonstrated that the Y chromosome of this African American individual carried the ancestral state of all known Y chromosome SNPs. To further characterize this lineage, which we dubbed A00 (see Figure S1, available online, for proposed nomenclature)"; "We have renamed the basal branch in Cruciani et al.  as A0 (previously A1b) and refer to the presently reported lineage as A00. For deep branches discovered in the future, we suggest continuing the nomenclature A000, and so on."
- At first (Mendez et al. 2013) this was announced as "extremely ancient" (95% confidence interval 237–581 kya for the age of the Y-MRCA including the lineage of this postulated haplogroup).
- Albert Perry, a slave born in the United States between ca. 1819–1827, lived in York County, South Carolina. See FamilyTreeDNA, Haplogroup A chart
- Mendez et al. (2013), p. 455. Quote: "Upon searching a large pan-African database consisting of 5,648 samples from ten countries [...] we identified 11 Y chromosomes that were invariant and identical to the A00 chromosome at five of the six Y-STRs (2 of the 11 chromosomes carried DYS19-16, whereas the others carried DYS19-15). These 11 chromosomes were all found in a sample of 174 (~6.3%) Mbo individuals from western Cameroon (Figure 2). Seven of these Mbo chromosomes were available for further testing, and the genotypes were found to be identical at 37 of 39 SNPs known to be derived on the A00 chromosome (i.e., two of these genotyped SNPs were ancestral in the Mbo samples)".
- Which of Cameroon's peoples have members of haplogroup A00? // experiment.com update of funded research (Schrack/Fomine Forka) available online Quotes: We can now clearly see that with 40% A00, the Bangwa represent the epicentre of A00 in this region, and very possibly in the world. As I shared in the last Lab Note, we found that so far there are two main subgroups of A00, defined by different Y-SNP mutations, which, naturally, divide along ethnic lines: A00a among the Bangwa, and A00b among the Mbo. We also found the one Bangwa sample which didn't belong to either subgroup.".
- Lipson Mark et al. Ancient Human DNA from Shum Laka (Cameroon) in the Context of African Population History // SAA 2019
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- Hisham Y. Hassan et al. (2008). "Southern Sudanese" includes 26 Dinka, 15 Shilluk, and 12 Nuer. "Western Sudanese" includes 26 Borgu, 32 Masalit, and 32 Fur. "Northern Sudanese" includes 39 Nubians, 42 Beja, 33 Copts, 50 Gaalien, 28 Meseria, and 24 Arakien.
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- Flores C, Maca-Meyer N, Larruga JM, Cabrera VM, Karadsheh N, Gonzalez AM (2005). "Isolates in a corridor of migrations: a high-resolution analysis of Y-chromosome variation in Jordan". J. Hum. Genet. 50 (9): 435–41. doi:10.1007/s10038-005-0274-4. PMID 16142507.
- Mohamed, Hisham Yousif Hassan. "Genetic Patterns of Y-chromosome and Mitochondrial DNA Variation, with Implications to the Peopling of the Sudan" (PDF). University of Khartoum. p. 76. Retrieved 22 August 2016.
- Karafet TM, Mendez FL, Meilerman MB, Underhill PA, Zegura SL, Hammer MF (2008). "New binary polymorphisms reshape and increase resolution of the human Y chromosomal haplogroup tree". Genome Research. 18 (5): 830–8. doi:10.1101/gr.7172008. PMC 2336805. PMID 18385274.
- ISOGG, 2016, Y-DNA Haplogroup Tree 2016. (Access: 29 August 2017.)
- Mendez FL, Krahn T, Schrack B, et al. (March 2013). "An African American paternal lineage adds an extremely ancient root to the human Y chromosome phylogenetic tree". Am. J. Hum. Genet. 92 (3): 454–9. doi:10.1016/j.ajhg.2013.02.002. PMC 3591855. PMID 23453668. as PDF
- "Y-Haplogroup A Phylogenetic Tree". March 2013. Retrieved 30 March 2013. (chart highlighting new branches added to the A phylotree in March 2013)
|Wikimedia Commons has media related to Haplogroup A of Y-DNA.|
- Family Tree DNA — Y-Haplogroup A Project
- African Haplogroup project at FTDNA
- Spread of Haplogroup A, from National Geographic
|A00||A0-T [χ 3]|
|A0||A1 [χ 4]|
|I||J||LT [χ 5]||K2 [χ 6]|
|L||T||K2a [χ 7]||K2b [χ 8]||K2c||K2d||K2e [χ 9]|
|K-M2313 [χ 10]||K2b1 [χ 11]||P [χ 12]|
|NO||S [χ 13]||M [χ 14]||P1||P2|