Haplogroup R1

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In human genetics, Haplogroup R1 is a Y-chromosome DNA haplogroup, a subgroup of haplogroup R, associated with the M173 mutation. It is dominated in practice by two very common Eurasian clades, R1a and R1b, which together are found all over Eurasia except in Southeast Asia and East Asia. However other types of R1, less well-known and defined and therefore referred to collectively simply as R1* or R-M173*, have been found in significant concentrations in Central Africa, Jordan, and Central Asia.

Origins

The origins of R1 remain unclear. On the one hand there is a significant presence as far south as Central Africa, for example Cameroon. Although this is generally seen as a result of back migration from Eurasia, it has been seen, especially in conjunction with high levels of R1* in Jordan, as indicative of the likelihood that R1 had origins in the Middle East.

On the other hand, R1's sibling clade, R2, is South Asian and generally considered to have originated in or near South Asia. This suggests an origin for R1 to the east of the Middle East. For example, Kivisild et al. (2003) believes the evidence "suggests that southern and western Asia might be the source of this haplogroup".^[3]

Looking at R1's relatives more generally, haplogroup R is part of the family of haplogroup P, and a sibling clade therefore, of haplogroup Q, which is common in the Americas, and in Eurasia is associated with eastern areas such as Siberia.

Distribution

R1 is very common throughout all of Eurasia except East Asia and Southeast Asia. Its distribution is believed to be associated with the re-settlement of Eurasia following the last glacial maximum. Its main subgroups are R1a (M420) and R1b (M343). One subclade of haplogroup R1b (especially R1b1b2, R-M269), is the most common haplogroup in Western Europe, while another R1a (especially R1a1a, R-M17 or R-M98) is the most common haplogroup in Eastern Europe as well as some parts of Central Asia, South Asia, Western China, and South Siberia.^[4]

One isolated clade (or clades) of Y chromosomes that appear to belong to Haplogroup R1b1* (P25-derived) is found at high frequency among the native populations of northern Cameroon, such as the Kirdi, in west-central Africa, which is believed to reflect a prehistoric back-migration of an ancient proto-Eurasian population into Africa.

Individuals whose Y-chromosomes possess all the mutations on internal nodes of the Y-DNA tree down to and including M207 (which defines Haplogroup R) but which display neither the M173 mutation that defines Haplogroup R1 nor the M124 mutation that defines Haplogroup R2 are categorised as belonging to group R*. Haplogroup R* has been found in 10.3% (10/97) of a sample of Burusho and 6.8% (3/44) of a sample of Kalash from northern Pakistan.^[5]

Subclades

The subclades of haplogroup R with their defining mutation, according to the stratification chart published by the 2009 International Society of Genetic Genealogy (ISOGG)^[6]:

• R*
• R1 (M173/P241, P225, P231, P233, P234, P236, P238, P242, P286, P294)
  • R1a (L62, L63) is typical in populations of parts of Europe and Asia
    • • R1a1a (M17, M198)
        • R1a1a1 (M56)
        • R1a1a2 (M157)
        • R1a1a3 (M64.2, M87, M204)
        • R1a1a4 (P98)
        • R1a1a5 (PK5)
  • R1b (M343) Typical of populations of Western Europe, with a moderate distribution throughout Eurasia and in parts of Africa
    • R1b1 (P25)
      • R1b1a (M18)
      • R1b1b (P297)
        • R1b1b1 (M73)
        • R1b1b2 (M269, S3, S10, S13, S17)
          • R1b1b2a (L23/S141, L49)
            • R1b1b2a1 (L51)
              • R1b1b2a1a (L11/S127, L52, P310/S129, P311/S128)
                • R1b1b2a1a1 (M405/S21/U106)
                  • R1b1b2a1a1a (M467/S29/U198)
                  • R1b1b2a1a1b (P107 (position relative to L48 uncertain))
                  • R1b1b2a1a1c (DYS439(null)/L1/S26)
                  • R1b1b2a1a1d (L48/S162)
                    • R1b1b2a1a1d1 (L47)
                      • R1b1b2a1a1d1a (L44, L45, L46)
                • R1b1b2a1a2 (P312/S116)
                  • R1b1b2a1a2a (M65)
                  • R1b1b2a1a2b (M153)
                  • R1b1b2a1a2c (M167/SRY2627)
                  • R1b1b2a1a2d (S28/U152)
                    • R1b1b2a1a2d1 (M126 (position relative to L2/S139 uncertain))
                    • R1b1b2a1a2d2 (M160 (position relative to L2/S139 uncertain))
                    • R1b1b2a1a2d3 (L2/S139)
                      • R1b1b2a1a2d3a (L20/S144)
                  • R1b1b2a1a2e (S68)
                  • R1b1b2a1a2f (L21/S145)
                    • R1b1b2a1a2f1 (M37)
                    • R1b1b2a1a2f2 (M222/USP9Y+3636)
                    • R1b1b2a1a2f3 (P66)
      • R1b1c (M335)

R1

Distribution of R1a (purple) and R1b (red)

Haplogroup R1 contains the majority of representatives of haplogroup R in the form of its subclades, R1a and R1b.^[7][8][9]

R1a

The highest levels of R1a (>50%) are found found in certain populations in Eurasia, from Central Europe to Northern India and Western China: Kashmiri Pandits (72%), the Ishkashimi (68%), the Tajik population of Khojant (64%), Kyrgyz (63.5%), Sorbs (63.39%), Poles (56.4%), and Ukrainians (54.0%)^{[10][11][12][8]} and in the central India among the sahariai tribe of North india (72%).^[13]

R1a has been variously associated with:

• the re-colonization of Eurasia during the Late Glacial Maximum.^[8][14]
• the expansion of the Kurgan people from the Pontic-Caspian steppe, which is associated with the spread of the Indo-European languages,^[8][11]
• The Modern Recent single-origin hypothesis ties in with R1a1 (M17) that it "could have found his way initially from India or Pakistan, through Kashmir, then via Central Asia and Russia, before finally coming to Europe"..."as part of an archaeologically dated Paleolithic movement from east to west 30,000 years ago."^[15].

R1b

Haplogroup R1b probably originated in Eurasia prior to or during the last glaciation. It is the most common haplogroup in Western Europe and may have survived the LGM concentrated in refugia in southern Europe and the Aegean.

It is also present at lower frequencies throughout Eastern Europe, with higher diversity than in western Europe, suggesting an ancient migration of R1b from the east.^[16] R1b is also found at various frequencies in many different populations near the Ural Mountains and Central Asia, its likely region of origin.

It is also found in North Africa where its frequency surpasses 10% in some parts of Algeria^[17]. In south-eastern England the frequency of R1b is about 70%; in parts of the rest of north and western England, Spain, Portugal, Wales and Ireland, it is as high as 90%; and in parts of north-western Ireland it reaches 98%. The R1b clade appears to have a much higher degree of internal diversity than R1a, which suggests that the M343 mutation that derives R1b from R1* may have occurred considerably earlier than the SRY1532 mutation that defines R1a.

R1b (previously called Hg1 and Eu18) is the most frequent Y-chromosome haplogroup in Europe. It is an offshoot of R1 (M173), characterised by the M343 marker.^[18] An overwhelming majority of members of R1b are classified as R1b1 (defined by the P25 marker), the remainder as R1b*. Its frequency is highest in Western Europe (and due to modern European emigration, in parts of the Americas). The majority of R1b-carriers of European descent belong to the subclade R1b1b2 (M269).

Notes

References

• Luigi Luca Cavalli-Sforza (1994). The History and Geography of Human Genes. Princeton University Press.  ISBN 0-691-08750-4
• Semino et al. (2000), "The Genetic Legacy of Paleolithic Homo sapiens sapiens in Extant Europeans" (PDF), Science 290, http://hpgl.stanford.edu/publications/Science_2000_v290_p1155.pdf .
• Wells et al. (2001), "The Eurasian Heartland: A continental perspective on Y-chromosome diversity" (PDF), PNAS 98, http://www.pnas.org/cgi/reprint/98/18/10244.pdf .
• Passarino et al. (2002), "Different genetic components in the Norwegian population revealed by the analysis of mtDNA and Y chromosome polymorphisms", Eur. J. Hum. Genet. 10 (9): 521–9, PMID 12173029, http://www.nature.com/ejhg/journal/v10/n9/full/5200834a.html .
• Behar et al. (2003), "Multiple Origins of Ashkenazi Levites: Y Chromosome Evidence for Both Near Eastern and European Ancestries", Am. J. Hum. Genet. 73: 768–779, PMID 13680527, http://www.journals.uchicago.edu/AJHG/journal/issues/v73n4/40097/40097.html .
• Saha Anjana, Sharma Swarkar, Bhat Audesh,Pandit Awadesh, Bamezai Ramesh (2005). Genetic affinity among five different population groups in India reflecting a Y-chromosome gene flow. J Hum Genet;50:49–51 PMID 15611834
• Sanghamitra Sengupta et al. (2006), Polarity and Temporality of High-Resolution Y-Chromosome Distributions in India Identify Both Indigenous and Exogenous Expansions and Reveal Minor Genetic Influence of Central Asian Pastoralists, American Journal of Human Genetics, 78:202-221
• C. Cinnioglu et al. (2004), Excavating Y-chromosome haplotype strata in Anatolia, Human Genetics 114(2):127-48.

See also

• Human Y-chromosome DNA haplogroup
• Genealogical DNA test
• Prehistoric Europe
• Y-DNA haplogroups by ethnic groups
• R-Arabia Y-DNA Project