Haplogroup R (Y-DNA)

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Haplogroup R

Time of origin 26,800 years BP[1]
Place of origin -
Ancestor P
Descendants R1a, R1b, R2
Defining mutations M207

In human genetics, Haplogroup R is a Y-chromosome DNA haplogroup, a subgroup of haplogroup P, associated with the M207 mutation.

Contents

[edit] Origins

It is believed to have occurred somewhere in Northwest Asia between 30,000 and 35,000 years ago. However, most of the rare forms of Haplogroup R chromosomes, as well as most cases of the closely related Haplogroup Q, are found among populations of Central Asia, South Asia, Australia, Siberia, Native Americans, Egypt and Cameroon.


Haplogroup R
Haplogroup R1
Haplogroup R1a

Haplogroup R1a1



Haplogroup R1b



Haplogroup R2



[edit] Distribution

The majority of members of haplogroup R belong to the Haplogroup R1, defined by marker M173. R1 is very common throughout Europe and western Eurasia. Its distribution is believed to be associated with the re-settlement of Eurasia following the last glacial maximum. Its main subgroups are R1a (SRY1532) and R1b (M343).

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 in west-central Africa, which is believed to reflect a prehistoric back-migration of an ancient proto-Eurasian population into Africa; some researchers have reported having also detected Haplogroup T Y-chromosomes at a low frequency among some of these Cameroonian populations, which also suggests a Eurasian affinity.[2] Some Y-chromosomes that appear to be closely related to the northern Cameroonian R1b1* are found at a substantial frequency among the modern population of Egypt. Many modern populations of northern Cameroon speak Chadic languages, which are classified as an ancient branch of the Afro-Asiatic superfamily of languages; the now extinct language of the Ancient Egyptians also belonged to the same superfamily.

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*. Some instances of Haplogroup R* have been reported from samples of Australian aboriginal populations. Haplogroup R* has also 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.[3]

[edit] Subclades

The subclades of haplogroup R with their defining mutation, according to the stratification chart published by the 2006 International Society of Genetic Genealogy (ISOGG)[4]:

  • R*
  • R1 (M173)
    • R1a (SRY10831.2 (SRY1532)) Typical of populations of Eastern Europe, Central Asia, and South Asia, with a moderate distribution in Western Europe, Southwest Asia, and southern Siberia
      • R1a1 (M17, M198)
        • R1a1a (M56)
        • R1a1b (M157)
        • R1a1c (M64.2, M87, M204)
        • R1a1*
      • R1a*
    • R1b (M343) Typical of populations of Western Europe, with a moderate distribution throughout Eurasia and in parts of Africa
      • R1b1 (P25)
        • R1b1a (M18)
        • R1b1b (M73)
        • R1b1c (M269, S3, S10, S13, S17)
          • R1b1c1 (M37)
          • R1b1c2 (M65)
          • R1b1c3 (M126)
          • R1b1c4 (M153)
          • R1b1c5 (M160)
          • R1b1c6 (SRY2627, M167)
          • R1b1c7 (M222)
          • R1b1c8 (P66)
          • R1b1c9 (S21)
            • R1b1c9a (S26)
            • R1b1c9b (S29)
            • R1b1c9*
          • R1b1c10 (S28)
          • R1b1c*
        • R1b1d (M335)
        • R1b1*
      • R1b*
    • R1*
  • R2 (M124) Typical of populations of South Asia, with a moderate distribution in Central Asia and the Caucasus

[edit] R*

R* is found in both Central and South Asians, including 10.3% (10/97) of Burusho and 6.8% (3/44) of Kalash.[3] Some instances of R* have been reported from samples of Australian aboriginal populations.

[edit] R1

Distribution of R1a (purple) and R1b (red)
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.[5][6][7]

[edit] R1a

Main article: Haplogroup R1a (Y-DNA)

The highest levels of R1a (>50%) are found along the Eurasian Steppe: the Ishkashimi (68%), the Tajik population of Khojant (64%), Sorbs (63.39%), Kyrgyz (63%), Hungarians (60.0%), Poles (56.4%), and Ukrainians (54.0%).[8][9][6]

R1a has been variously associated with:

R1a1 provides genetic corroboration of the Kurgan theory of Indo-European origins, and suggests that the Sredny Stog and Yamnaya cultures of the Pontic Steppe region north of the Black Sea in modern day Ukraine were the Proto-Indo-Europeans.

[edit] R1b

Main article: Haplogroup R1b (Y-DNA)

Haplogroup R1b originated prior to or during the last glaciation, when it was concentrated in refugia in southern Europe and the Aegean. It is the most common haplogroup in Western Europe, but has been found at low frequency as far away as Korea. It is also found in North Africa where its frequency surpasses 10% in some parts of Algeria[11]. 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.[12] 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 R1b1c (M269).

[edit] R2

Main article: Haplogroup R2 (Y-DNA)

At least 90% of R2 individuals are located in the Indian sub-continent.[13] It is also reported in Caucasian and Central Asian populations.

R2 (M124) arose about 25,000 years ago in southern Central Asia, and its members migrated southward as part of the second[14] major wave of human migration into India.[15]

[edit] Notes

  1. ^ Tatiana M. Karafet, Fernando L. Mendez, Monica B. Meilerman, Peter A. Underhill, Stephen L. Zegura, and Michael F. Hammer (2008). New binary polymorphisms reshape and increase resolution of the human Y chromosomal haplogroup tree
  2. ^ Mulcare, Charlotte A. et al (2004). "[http://www.journals.uchicago.edu/AJHG/journal/issues/v74n6/40808/40808.web.pdf The T Allele of a Single-Nucleotide Polymorphism 13.9 kb Upstream of the Lactase Gene (LCT) (C513.9kbT) Does Not Predict or Cause the Lactase-Persistence Phenotype in Africans]" ([dead link]). The American Journal of Human Genetics. 74: 1107. 
  3. ^ a b Sadaf Firasat, Shagufta Khaliq, Aisha Mohyuddin, Myrto Papaioannou, Chris Tyler-Smith, Peter A Underhill and Qasim Ayub, "Y-chromosomal evidence for a limited Greek contribution to the Pathan population of Pakistan," European Journal of Human Genetics (2007) 15, 121–126.
  4. ^ http://www.isogg.org/tree/Main06.html ISOGG Website
  5. ^ Haplogroup R1 (M173). The Genographic Project. National Geographic Society. Retrieved on 2008-03-11.
  6. ^ a b c d Semino et al. 2000
  7. ^ Rosser et al. 2000
  8. ^ a b Wells et al. (2001)
  9. ^ Behar et al. (2003)
  10. ^ Passarino et al. (2002)
  11. ^ Analysis of Y-chromosomal SNP haplogroups and STR haplotypes in an Algerian population sample
  12. ^ Note that in earlier literature the M269 marker, rather than M343, was used to define the R1b haplogroup. Then, for a time (from 2003 to 2005) what is now R1b1c was designated R1b3.
  13. ^ Manoukian (2006)
  14. ^ The first consisted of African migrants who traveled along the Indian coastline some 50,000 to 60,000 years ago.
  15. ^ The Genographic Project. National Geographic Society. Retrieved on 2008-03-13.

[edit] References

[edit] See also

Human Y-chromosome DNA (Y-DNA) haplogroups (by ethnic groups, famous haplotypes)
most recent common Y-ancestor
|
A BT
B CT
DE CF
D E C F
G H IJ K
I J L M NO P S T
N O Q R

[edit] External links