Haplogroup R2a (Y-DNA)

Haplogroup R2a
Possible time of origin 25,000 years BP
Possible place of origin South Asia or Central Asia
Ancestor R2
Descendants R2a*, R2a1, R2a2
Defining mutations M124, P249, P267, PAGES00004, L266, L381[1][2]

Haplogroup R2a is a Y-chromosome haplogroup characterized by genetic markers M124, P249, P267, L266, PAGES00004, and L381,[1][2] and is mainly found in South Asia, and in marginal frequency, parts of Central and West Asia.

Contents

Term history

Before the update of the 2010 Y-Chromosome Phylogenetic Tree on the 9th of September 2010, Haplogroup R2a was officially known as Haplogroup R2.[1] However, the first reference to the newly defined Haplogroup, R2a, was on the 25th of August 2010.[3]

Before the publication of the 2005 Y-Chromosome Phylogenetic Tree, Haplogroup R2a was known as Haplogroup P1 and formerly thought to be a sister clade of Haplogroup R rather than derived from it.[4]

Origins

According to the Genographic Project conducted by the National Geographic Society, Haplogroup R2 (Now R2a) arose about 25,000 years ago in Central Asia [4] and its members migrated southward as part of the second[5] major wave of human migration into India.[6]

According to Sengupta et al. (2006),

uncertainty neutralizes previous conclusions that the intrusion of HGs R1a1 and R2 (Now R2a) from the northwest in Dravidian-speaking southern tribes is attributable to a single recent event. Rather, these HGs contain considerable demographic complexity, as implied by their high haplotype diversity. Specifically, they could have actually arrived in southern India from a southwestern Asian source region multiple times, with some episodes considerably earlier than others.

The following is Manoukian's (2006) summary of the findings of the Genographic Project conducted by the National Geographic Society and directed by Spencer Wells (2001):

  • Haplogroup R, the ancestral clade to R1 and R2, appeared on the Central Asian Steppes around 35,000 to 30,000 years ago.
  • R1, sister clade to R2, moved to the West from the Central Asian Steppes around 35,000 to 30,000 years ago. R1 pockets were established, from where R1a and R1b emerged.
  • R2a made its first entry into the Indian sub-continent around 25,000 years ago. The routes taken are not clear, although the Indus and Ganges rivers are possible theories put forward. There could, of course, have been multiple immigrations of this haplogroup into the Indian sub-continent, both in the Paleolithic and the Neolithic.

Subclades

Haplogroup R2a 

 Paragroup R2a*


 Haplogroup R2a1


 Haplogroup R2a2


Paragroup R2a*

Paragroup is a term used in population genetics to describe lineages within a haplogroup that are not defined by any additional unique markers. They are typically represented by an asterisk (*) placed after the main haplogroup.

Y-chromosomes which are positive to the M124, P249, P267, L266, PAGES00004, & L381 SNPs and negative to the L295 & L263 SNPs, are categorized as belonging to Paragroup R2a*.

Haplogroup R2a1

Haplogroup R2a1 is a Y-chromosome haplogroup characterized by genetic marker L295. It is found in India, Armenia, Turkey, Italy, & Qatar so far.

Haplogroup R2a2

Haplogroup R2a2 is a Y-chromosome haplogroup characterized by genetic marker L263. It is found in Greece & Armenia so far.[7]

Distribution

At least 90% of R2a individuals are located in the Indian sub-continent.[4] It is also reported in Caucasus and Central Asia.

Manoukian's (2006) summary of Sengupta et al. (2006) is as follows:

  • Haplogroup R2a is present both in Dravidian and other Indian populations, meaning that R2a has a pan-Indian presence, and not restricted to any linguistic group.
  • Haplogroup R2a has a more significant presence in middle and upper castes.
  • The frequencies of R2a seem to mirror the frequencies of R1a (i.e. both lineages are strong and weak in the same social and linguistic subgroups). This may indicate that both R1a and R2a moved into India at roughly the same time or cohabited, although more research is needed.
  • R1a1 and R2a haplogroups indicate demographic complexity that is inconsistent with a recent single history and is not inconsistent with a more proximal Central Asian input of the R2a haplogroup in the upper castes.
  • R2a has a particularly strong presence in the Indian states of West Bengal, Uttar Pradesh and Gujarat, and in the area of Mumbai (Bombay).
  • The paper claims that there is no evidence that Central Asia was the source of the R1a and R2a lineages in India. The theory that Central Asia could have been the recipient of the two lineages from India should not be ruled out. In addition, the data are not inconsistent with complex exchanges of this haplogroup between Central Asia and the Indian sub-continent, with the latter being both the source and the recipient at different times.

South Asia

Frequency of R2a in Social and Linguistic Subgroups of Indian Populations
(Source: Sengupta et al. 2006)
Tibeto-Burman Austro-Asiatic Dravidian Indo-European
Tribe 5.75% 10.94% 5.00% -
Lower Caste - - 13.79% 10.00%
Middle Caste - - 3.53% 18.75%
Upper Caste - - 10.17% 16.28%

Haplogroup R2a, along with haplogroups H, L, R1a1, and J2, forms the majority of the South Asian male population. The frequency is around 10-15% in India and Sri Lanka and 7-8% in Pakistan. Its spread within South Asia is very extensive, ranging from Baluchistan in the west to Bengal in the east; Hunza in the north to Sri Lanka in the south.

Within South Asia, very high frequencies shown by some social groups include Karmali of West Bengal at (16/16) 100%, Jaunpur Kshatriya of Uttar Pradesh at (41/47) 87% and Kamma Chaudhary of Andhra Pradesh at (11/15) 73%. Other South Asian communities that have a reasonably high frequency include Sinhalese with (15/39) 38%, people of West Bengal at 23%, Lodha, an Austro-Asiatic tribe in East India with 43%, Pallans, a Dravidian community in South India with 14%, Konkanastha or Chitpavan Brahmins of Western India with 26% and Punjabi Brahmins of North India with 25%. The data reported by Sengupta (2006) show a prevalence of 20% (10/51) of this haplogroup in the three Indo-European-speaking Brahmin groups (Uttar Pradesh, West Bengal, Konkanasth). This lineage also forms 5% of Punjabi males. North Indian Muslims have a frequency of 11%(Sunni) and 9%(Shia), while Dawoodi Bohra Muslim in the western state of Gujarat have a frequency of 16% and Mappla Muslims of South India have a frequency of 5%.[8] The R2a haplogroup is also found in 14% of the Burusho people who speak the language isolate called Burushaski.[9]

Some of the other studies like Bamshad et al., 2001, Kivisild et al., 2003 found Haplogroup 1(the old representation for non-R1a1 Haplogroup R subclades) at around 40% among Telugus of coastal Andhra Pradesh. The identification of this Haplogroup with R2a is confirmed from Sanghamitra Sahoo et al., 2006 study which observed R2a ranging from 35% to 55% among non-Brahmin castes of this region.

Haplogroup R2a comprises 53% of Y-chromosomes among Sinti, a subgroup of the Romani people living in Germany who were relocated to Central Asia, however the sample size was only 15 individuals. This Romani branch has its ancient roots in India.

Central Asia

In Central Asia, Tajikistan shows Haplogroup R2a at 6%, while the other '-stan' states vary around 2%. Bartangis of Tajikistan have a high frequency of R2a at about 17%, Ishkashimi at 8%, Khojant at 9% and Dushanbe at 6%.

Specifically, Haplogroup R2a has been found in approximately 7.5% (4/53) of recent Iranian emigrants living in Samarkand,[10] 7.1% (7/99) of Pamiris,[10] 6.8% (3/44) of Karakalpaks,[10] 5.1% (4/78) of Tajiks,[10] 5% (2/40) of Dungans in Kyrgyzstan,[10] 3.3% (1/30) of Turkmens,[10] 2.2% (8/366) of Uzbeks,[10] and 1.9% (1/54) of Kazakhs.[10]

Caucasus

One study has found Haplogroup R2a at an unusually high frequency of 44% (11/25) among Kurmanji speakers (Kurmanjs) in Georgia, but at a much lower frequency of 8% (7/87) among Kurmanjs in Turkey.[11]

An R2a frequency of 15.8% was observed among Chechens.[12] R2a has been found in approximately 8% (2/24) of a sample of Ossetians from Alagir.[13]

In the Caucasus, around 8% of Balkarians,[14] 6% of Kalmyks,[15] 3% of Azerbaijanis,[12] 2.6% of Kumyks,[16] 2.4% of Avars,[16] 2% of Armenians,[12] and 1% to 6% of Georgians[12][14][17] belong to the R2a haplogroup. Approximately 1% of Turks[18] and 1% to 3% of Iranians[19] also belong to this haplogroup.

Arab World

Frequency of Haplogroup R2a in the Arab World from DNA studies
Count Sample Size R2a Fequency %
UAE[20] 8 217 3.69%
Qatar[21] 1 72 1.39%
Kuwait[22] 1 153 0.65%
Yemen[21] 1 104 0.96%
Jordan[23] 2 146 1.37%
Lebanon[24] 2 935 0.21%
Palestine[25] 1 49 2.04%
Egypt[26] 1 147 0.68%

In the R2-M124-WTY and R-Arabia Y-DNA Projects,[7][27] Haplogroup R2a has appeared in the following Arab countries: Kuwait (2 clusters), Saudi Arabia (2 clusters), United Arab Emirates (1 cluster), Syrian Arab Republic (1 cluster), and Tunisia (1 cluster).

Thus, Haplogroup R2a has been observed among Arabs at low frequencies in 11 countries/territories (Egypt, Jordan, Kuwait, Lebanon, Palestine, Qatar, Saudi Arabia, Syria, Tunisia, United Arab Emirates, and Yemen) of the 22 Arab countries/territories so far.

Position on the ISOGG tree and related SNPs

Haplogroup R2a is a subgroup of Haplogroup R2 (M479):

Evolutionary tree of Human Y-chromosome DNA (Y-DNA) haplogroups
most recent common Y-ancestor
A
A1b A1a-T
A1a A2-T
A2 A3 BT
B CT
DE CF
D E C F
G H IJK
IJ K
I J LT K(xLT)
L T M NO P S
O N Q R

Y-DNA by populations · Famous Y-DNA haplotypes

Prediction with Haplotypes

Haplotype can be used to predict haplogroup. The chances of any person part of this haplogroup is the highest if DYS391=10, DYS392=10 and DYS426=12.

See also

Notes

  1. ^ a b c ISOGG (2010), "Y-DNA Haplogroup R and its Subclades - 2010."
  2. ^ a b FTDNA's Draft phylogeny tree, "FTDNA's Draft phylogeny tree."
  3. ^ Myres et al. (2010), "A major Y-chromosome haplogroup R1b Holocene era founder effect in Central and Western Europe - 2010."
  4. ^ a b c Manoukian, Jean-Grégoire (2006), "A Synthesis of Haplogroup R2 - 2006."
  5. ^ The first consisted of African migrants who traveled along the Indian coastline some 50,000 to 60,000 years ago.
  6. ^ National Geographic Society (2005). "Atlas of the Human Journey". The Genographic Project. Washington DC: National Geographic Society. https://www3.nationalgeographic.com/genographic/atlas.html .
  7. ^ a b R2-M124-WTY (Walk Through the Y) Project, "R2-M124-WTY (Walk Through the Y) Project."
  8. ^ Muthukrishnan Eaaswarkhanth, Ikramul Haque, Zeinab Ravesh, Irene Gallego Romero, Poorlin Ramakodi Meganathan, Bhawna Dubey, Faizan Ahmed Khan, Gyaneshwer Chaubey, Toomas Kivisild, Chris Tyler-Smith, Lalji Singh and Kumarasamy Thangaraj. Traces of sub-Saharan and Middle Eastern lineages in Indian Muslim populations. 
  9. ^ Firasat S, Khaliq S, Mohyuddin A, Papaioannou M, Tyler-Smith C, Underhill PA, Ayub Q. Y-chromosomal evidence for a limited Greek contribution to the Pathan population of Pakistan. 
  10. ^ a b c d e f g h R.Spencer Wells et al, The Eurasian Heartland: A continental perspective on Y-chromosome diversity, PNAS August 28, 2001, vol. 98 no. 18, pp.10244-10249.
  11. ^ Nasidze et al.; Quinque, D; Ozturk, M; Bendukidze, N; Stoneking, M (2005). "MtDNA and Y-chromosome Variation in Kurdish Groups". Annals of Human Genetics 69 (Pt 4): 401–412. doi:10.1046/j.1529-8817.2005.00174.x. PMID 15996169. 
  12. ^ a b c d Nasidze et al.; Sarkisian, T; Kerimov, A; Stoneking, M (2003). "Testing hypotheses of language replacement in the Caucasus: evidence from the Y-chromosome". Hum Genet 112 (3): 255–261. doi:10.1007/s00439-002-0874-4. PMID 12596050.  [1]
    Manoukian (2006)
  13. ^ I. Nasidze, D. Quinque, I. Dupanloup et al., "Genetic Evidence Concerning the Origins of South and North Ossetians," Annals of Human Genetics (2004) 68, 588–599
  14. ^ a b Vincenza Battaglia, Simona Fornarino, Nadia Al-Zahery et al., "Y-chromosomal evidence of the cultural diffusion of agriculture in southeast Europe," European Journal of Human Genetics (2008), 1 – 11
  15. ^ Ivan Nasidze, Dominique Quinque, Isabelle Dupanloup, Richard Cordaux, Lyudmila Kokshunova, and Mark Stoneking, "Genetic Evidence for the Mongolian Ancestry of Kalmyks," American Journal of Physical Anthropology 126:000–000 (2005).
  16. ^ a b Yunusbaev et al. (2006): 2/76 = 2.6% R2a Kumyks, 1/42 = 2.4% R2a Avars
  17. ^ Semino, A; Passarino G, Oefner PJ, Lin AA, Arbuzova S, Beckman LE, De Benedictis G, Francalacci P, Kouvatsi A, Limborska S, Marcikiae M, Mika A, Mika B, Primorac D, Santachiara-Benerecetti AS, Cavalli-Sforza LL, Underhill PA (2000). "The Genetic Legacy of Paleolithic Homo sapiens sapiens in Extant Europeans: A Y Chromosome Perspective" (PDF). Science 290 (5494): 1155–59. doi:10.1126/science.290.5494.1155. PMID 11073453. http://hpgl.stanford.edu/publications/Science_2000_v290_p1155.pdf. 
  18. ^ Cinnioğlu et al. (2003), "Excavating Y-chromosome haplotype strata in Anatolia."
  19. ^ Regueiro M, Cadenas AM, Gayden T, Underhill PA, Herrera RJ (2006). "Iran: tricontinental nexus for Y-chromosome driven migration". Hum. Hered. 61 (3): 132–43. doi:10.1159/000093774. PMID 16770078. 
  20. ^ Alshamali et al. (2009), "Local Population Structure in Arabian Peninsula Revealed by Y-STR Diversity."
  21. ^ a b Cadenas et al. (2007), "Y-chromosome diversity characterizes the Gulf of Oman."
  22. ^ Mohammad et al. (2009), "Genetic structure of nomadic Bedouin from Kuwait."
  23. ^ Flores et al. (2005), "Isolates in a corridor of migrations: a high-resolution analysis of Y-chromosome variation in Jordan."
  24. ^ Zalloua et al. (2008), "Y-Chromosomal Diversity in Lebanon Is Structured by Recent Historical Events."
  25. ^ Myres et al. (2010), "A major Y-chromosome haplogroup R1b Holocene era founder effect in Central and Western Europe."
  26. ^ Luis et al. (2004), "The Levant versus the Horn of Africa: Evidence for Bidirectional Corridors of Human Migrations."
  27. ^ R-Arabia Y-DNA Project, "R-Arabia Y-DNA Project."

References

External links