Haplogroup R1a (Y-DNA)

A subclade of R1, R1a is a Y-chromosome haplogroup found at high frequency in the extreme north of India among the Kashmiri Pandits (72%)^[1], and more than 40% from the Czech Republic across to the Altai Mountains in Siberia and south throughout Central Asia.^[2]

R1a arose 15,000 years ago in the vicinity of Ukraine, expanding from either the Ukrainian LGM refuge following the end of the last ice age, or from the Pontic-Caspian steppe as a result of the Kurgan migrations.^[3][4][5]. But some studies question these earlier findings and claim that R1a lineages may have their origins in North India ^{[6][7] [8]}. The expansion of R1a, R2 and J2 has been associated with the spread of the Indo-European languages.^[3][4]

[edit] Origins

European LGM refuges, 20 kya.

Although in south east Europe the R1a haplogroup occurs at just 16% frequency, high-resolution Y chromosome analysis by Pericic et al. (2005) shows a maximum diversity of R1a STR variance among mainland Croatians and Bosnians. At the current resolution level the influence of gene flow to this effect is not fully understood:

At least three major episodes of gene flow might have enhanced R1a variance in the region: early post-LGM recolonizations expanding from the refugium in Ukraine, migrations from northern Pontic steppe between 3000 and 1000 B.C., as well as possibly massive Slavic migration from A.D. 5th to 7th centuries.

The gene reach maximum distribution frequencies in Poland and in the Ukraine.

Kivisild et al. (2003) suggested that southern and western Asia might be the source of R1 and R1a differentiation.^[9]

Historical distribution of the Slavic languages. The area shaded in light purple is the Prague-Penkov-Kolochin complex of cultures of the 6th to 7th c. AD, likely corresponding to the spread of Slavic tribes at the time. The area shaded in darker red indicates the core area of Slavic river names (after EIEC p. 524ff.)

Earlier, Spencer Wells, director of the Genographic Project at the National Geographic Society, identified southern Russia/Ukraine as the likely origin of R1a (as identified by genetic marker M17) on the basis of both microsatellite diversity and frequency distribution.

Microsatellite diversity is greatest in southern Russia and Ukraine, suggesting that it arose there.^[2]

The current distribution of the M17 haplotype is likely to represent traces of an ancient population migration originating in southern Russia/Ukraine, where M17 is found at high frequency(>50%).^[4]

Archaeological cultures associated with Indo-Iranian migrations (after EIEC). The Andronovo, BMAC and Yaz cultures are associated with early Indo-Iranian, expansion, the Swat, Copper Hoard and PGW cultures with Indo-Aryan expansion into the Indian subcontinent.

Wells et al. (2001) support spread of R1a with the expansion of the Kurgan people around 3,000 B.C., which may have been driven by the domestication of the horse, which also took place in southern Russia/Ukraine at about the same time:

The current distribution of the M17 haplotype is likely to represent traces of an ancient population migration originating in southern Russia/Ukraine, where M17 is found at high frequency(>50%). It is possible that the domestication of the horse in this region around 3,000 B.C. may have driven the migration. The distribution and age of M17 in Europe and Central/Southern Asia is consistent with the inferred movements of these people, who left a clear pattern of archaeological remains known as the Kurgan culture, and are thought to have spoken an early Indo-European language. The decrease in frequency eastward across Siberia to the Altai-Sayan mountains (represented by the Tuvinian population) and Mongolia, and southward into India, overlaps exactly with the inferred migrations of the Indo-Iranians during the period 3,000 to 1,000 B.C.

Passarino et al. (2002) support the Ukrainian LGM refuge scenario, that R1a expanded from the area of the Dniepr-Don Valley in Ukraine between 13 000 and 7600 years ago, after the Last Glacial Maximum receded.

Semino et al. (2000) propose a synthesis of these two explanations, suggesting that the spread of R1a from a point of origin in Ukraine following the Last Glacial Maximum may have been magnified by the expansion of males from the Kurgan culture area of present-day southern Ukraine, where according to Gimbutas proposals^[10] Indo-European languages spread from. Within this context, the study also reminds the existence of an alternative hypothesis proposed on the basis of archeological data,^[11] pointing to a Middle Eastern origin of the language family instead (see Urheimat hypotheses).

Investigation of SNP and STR markers in the Czech Republic, however, that focus on frequently related to diversity occurring within subgroup R1a1 (and two other prominent YDNA groupings), confirmed that the results are compatible with a presence of the gene during or soon after the LGM. Without any reference to Kurgan invasions, the Czech population appears to be influenced though, to a very moderate extent, by genetic inputs (E3b, J2) from outside Europe in the post-Neolithic and historical times. Population growth beginning in the first millennium B.C. was detected and found characteristic for a gene pool that already contained R1a1, next to I-M170 and P*(xR1a1).^[12] The overall diversity suggests a rapid demographic expansion beginning about 60 to 80 generations ago, which would equate to about 1500 years ago (approx. 500 AD) to 2000 years ago (approx. 1 AD) with a generation time of 25 years. Similar results have been found in Lithuania.^[13]

[edit] Subclades

• R1a (SRY1532)
  • R1a1 (M17, M198) Typical of Eastern Europeans, Central Asians, and South Asians
    • R1a1a (M56) Found in a significant minority of people of Eastern Europe
    • R1a1b (M157) Found at low frequency in Scotland, Ireland and France
    • R1a1c (M64.2, M87, M204) Found at low frequency in Scotland and Ireland
    • R1a1*
  • R1a*

[edit] Distribution

Haplogroup R1a Distribution

R1a is "present at high frequency (40 per cent plus) from the Czech Republic across to the Altai Mountains in Siberia and south throughout Central Asia."^[2] To the east, this gene found its way as far as Eastern Siberia, with considerable concentrations in Kamchatka and Chukotka, and it is possible that the gene even entered the Americas by this route.^[14]

The modern population of Ukraine has the highest level of diversity of the gene making it the likeliest location of its origin.^[3][15][2] this map^[16] Even in South Eastern Europe (not a major concentration of R1a1) microsatellite networks of major Y chromosomal lineages show high diveristy of R1a1 (graph C)^[16]. The variance cluster in South Eastern Europe (SEE) is located in the Republic of Macedonia.^{[citation needed]}

[edit] Europe

In Europe, R1a is found primarily in the eastern part of the continent, with the highest frequencies among the Sorbs (63.39%), Poles (56.4%),^[3] , Russians (50.0%)^[17] and Ukrainians (54.0%).^{[3] [18]} An early study reported an R1a frequency of 60.0% among a sample of 45 Hungarians,^[3] but a more recent study found haplogroup R1a Y-DNA in only 20.4% of a sample of 113 Hungarians.^[19] The two main directional components of the spread are consistent with an East to West migration as well as a radial spread from the Balkans.^{[citation needed]}

Pericic et al. (2005) suggest three possible explanations for the distribution of R1a variation:

At least three major episodes of gene flow might have enhanced R1a variance in the region: early post-LGM recolonizations expanding from the refugium in Ukraine, migrations from northern Pontic steppe between 3000 and 1000 B.C., as well as possibly massive Slavic migration from A.D. 5th to 7th centuries.

It is likely that Vikings settling in Britain and Ireland carried the the R1a lineage,^[5] which accounts for the presence of the haplogroup on those islands.^[20][21]

[edit] Central Asia

Exceptionally high frequencies of M17 are found among the Ishkashimi (68%), the Tajik population of Khojant (64%), and the Kyrgyz (63%), but are likely "due to drift, as these populations are less diverse, and are characterized by relatively small numbers of individuals living in isolated mountain valleys."^[4] (The frequency of the Tajik/Dushanbe population is, at 19%, far lower than the 64% frequency of the Tajik/Khojant population.)^[4]

Haplogroup R1a is also common among Mongolic- and Turkic-speaking populations of Northwestern China, such as the Bonan, Dongxiang, Salar, and Uyghur peoples.^[22][23]

[edit] Iran

The gene has proven to be a "diagnostic Indo-Iranian marker," and "it is possible to represent traces of an ancient population migration originating in southern Russia/Ukraine," where it may have been driven by the domestication of the horse around 3,000 B.C.; its distribution and age are "consistent with the inferred movements of these people, who left a clear pattern of archaeological remains known as the Kurgan culture, and are thought to have spoken an early Indo-European language".^[4]

The frequency of R1a1 in western Iran, as in the Middle East, is only 5% to 10%, but in eastern Iran, the frequency of R1a1 is around 35%.^[24] Wells et al. (2001) suggest that the deserts of central Iran acted as "significant barriers to gene flow," and propose two possibilities:

Kivisild et al. (2003) on the other hand "suggests that southern and western Asia might be the source of this haplogroup":

[edit] India

Rosenberg et al. (2006) ran simulations dividing autosomal gene frequencies in selected populations into a given number of clusters. For 7 or more clusters, a cluster (yellow) appears which is nearly unique to the Kalash. Smaller amounts of Kalash gene frequencies join clusters associated with Europe and Middle East (blue) and with South Asia (red).

Further information: Genetics and archaeogenetics of South Asia

In a seminal work titled The Real Eve: Modern Man's Journey out of Africa (New York: Carroll and Graf Publishers, 2003), the prominent Oxford University scholar Stephen Oppenheimer concludes that South Asia is logically the ultimate origin of M17 and his ancestors.He observes:

In the "Peopling of South Asia: investigating the caste-tribe continuum in India", Chaubey G, Metspalu M, Kivisild T. et al arrive at the conclusion that both caste and tribal populations are autochthonous to India:"Molecular studies and archaeological record are both largely consistent with autochthonous differentiation of the genetic structure of the caste and tribal populations in South Asia. High level of endogamy created by numerous social boundaries within and between castes and tribes, along with the influence of several evolutionary forces such as genetic drift, fragmentation and long-term isolation, has kept the Indian populations diverse and distant from each other as well as from other continental populations."(Bioessays Jan 2007)

Recent studies suggest that R1a*, ancestral clade to Hg R1a1 arose in India. A study by S.Sharma et al published in the ASHG Abstracts 2007 screened 621 Y-chromosomes (of Brahmins, occupying upper most caste position and Dalits and Tribals with the lower most positions in the Indian caste hierarchical system) with fifty-five Y-chromosomal binary markers and Y-microsatellite markers and compiled a data set of 2809 Y-chromosomes (681 Bamins, 2128 Tribals and Dalits) for conclusions. Overall, no consistent difference was observed in Y-haplogroups distribution between Bamins, Dalits and Tribals, except for some differences confined to a given geographical region. The widespread distribution and high frequency across Eurasia and Central Asia of R1a1* as well as scanty representation of its ancestral (R*, R1* and R1a*) and derived lineages across the region has kept the origin of this haplogroup unresolved. The analyses of a pooled dataset of 530 Indians, 224 Pakistanis and 276 Central Asians and Eurasians,bearing R1a1* haplogroup resolved the controversy of origin of R1a1*. The conclusion was drawn on the basis of: i) presence of this haplogroup in many of the tribal populations such as, Saharia (present study) and Chenchu tribe in high frequency, ii) the highest ever reported presence of R1a* (ancestral haplogroup of R1a1*) in Kashmiri Pandits and Saharia tribe, and iii) associated averaged phylogenetic ages of R1a* (~18,478 years) and R1a1* (~13,768 years) in India.

However, Studies of India scholars showed the R1a lineage forms around 35–45% among all the castes in North Indian population (Namita Mukherjee et al. 2001) and the Badagas of the Nilgiris making the association with the Brahmin caste more vague. A further study (Saha et al 2005)^[25] examined R1a1 in South Indian tribals and Dravidian population groups more closely, and questioned the concept of its Indo-Iranian origin. Most recently Sengupta et al. (2006)^[26] have confirmed R1a's diverse presence including even Indian tribal and lower castes (the so-called untouchables) and populations not part of the caste system. From the diversity and distinctiveness of microsatellite Y-STR variation they conclude that there must have been an independent R1a1 population in India dating back to a much earlier expansion than the Indo-Aryan migration. Sengupta concludes saying North India including the Indus Valley contributed R1a1-M17 chromosomes to both the Central Asian and South Asian tribes much before the Indo-European event.

The pattern of clustering does not support the model that the primary source of the R1a1-M17 chromosomes in India was Central Asia or the Indus Valley via Indo-European speakers.^[27]

According to Sengupta et al. (table 5),^[26] R1* is virtually absent in Southeast and East Asia.

[edit] Haplotypes

[edit] Modal

The Eastern European Y-DNA-R1a Modal Haplotype can be found in Poland, Lithuania, Belarus and Ukraine. It has spread westwards into Germany, Bohemia, Moravia, Slovakia and Hungary. Ysearch: ANJNY

The English Y-DNA-R1a Modal Haplotype could have spread to the British Isles via the Anglo-Saxons, Vikings or Normans. Ysearch: AXEZU

[edit] Famous

Main articles: Somerled and Famous haplogroup members

In 2003 Oxford University researchers traced the Y-chromosome signature of Somerled of Argyll, one of Scotland's greatest warriors who is credited with driving out the Vikings. He was also the founder of Clan Donald and it is through the clan genealogies of the clan that the genetic relation was mapped out.^[28] Somerled belongs to haplogroup R1a1.

In 2005 a study by Professor of Human Genetics Bryan Sykes of Oxford University led to the conclusion that Somerled has possibly 500,000 living descendants - making him the second most common historical ancestor after Genghis Khan^[29]

The Y-DNA sequence is as follows (12 markers):^[30]

Ysearch: YS495

• Tõnu Trubetsky the descendant of Nikita Trubetskoy

Ysearch: WUZG2

• Anderson Cooper also belongs to Y-DNA haplogroup Haplogroup R1a.^[31]

[edit] Frequency

Main article: Y-DNA haplogroups by ethnic groups

R1a frequency is expressed as percentage of population samples.

[edit] Europe

	N	R1(xR1a1)	R1a1	source
Sorbs	112	-	63.39	Behar et al. (2003)
Hungarian	45	13.3	60.0	Semino et al. (2000)
Hungarian	113	20.4	20.4	Tambets et al. (2004)
Poles	55	16.4	56.4	Semino et al. (2000), Pericic et al. (2005)
Ukrainian	50	2.0	54.0	Semino et al. (2000), Pericic et al. (2005)
Belarusian	306		50.98	Behar et al. (2003)  ?- Pericic et al. (2005)
Russian	122	7.0	47.0	Pericic et al. (2005)
Belarusian	-		46	4
Belarusian	41	10.0	39.0	Pericic et al. (2005)
Ukrainian	-		44	3  ?
Ukrainians, Rashkovo	53		41.5	10  ?
Russian, North	49	0	43	5
Latvian	34	15.0	41.0	Pericic et al. (2005)
Udmurt	43	11.6	37.2	Semino et al. (2000)
Pomor	28	0	36	5
Macedonians	20	10.0	35.0	Semino et al. (2000)
Moldavians, Karahasan	72		34.7	10
Lithuanian	38	6	34	Pericic et al. (2005)
Croatian	58	10.3	29.3	Semino et al. (2000)
UK Orkney	26	65	27	5
Gagauzes, Etulia	41		26.8	10
Czech + Slovakian	45	35.6	26.7	Semino et al. (2000),14
Norwegian	83		26.5	13
Icelander	181	41.4	23.8	Pericic et al. (2005)
Norwegian	87		21.69	Behar et al. (2003)
Moldavians, Sofia	54		20.4	10
Orcandin	71	66.0	19.7	Pericic et al. (2005)
Swedish (Northern)	48	23.0	19.0	Pericic et al. (2005)
Swedish	110	20.0	17.3	Pericic et al. (2005)
Danish	12	41.7	16.7	Pericic et al. (2005)
Mari	46	0	13.0	Semino et al. (2000)
German	88		12.50	Behar et al. (2003)
German	48	47.9	8.1	Pericic et al. (2005)
Greek	76	27.6	11.8	Semino et al. (2000)
Albanian	51	17.6	9.8	Semino et al. (2000)
Saami	24	8.3	8.3	Semino et al. (2000)
UK Isle of Man	62	15	8	Capelli et al. (2003)
UK Orkney	121	23	7	Capelli et al. (2003)  ?? 7% <> 23% *5
UK	309		~7	13 see references
Georgian	63	14.3	7.9	Semino et al. (2000)
Turkish	523	16.3	6.9	Cinnioğlu et al. (2004)
UK Shetland	63	17	6	Capelli et al. (2003)
UK Chippenham	51	16	6	Capelli et al. (2003)
UK Cornwall	52	25	6	Capelli et al. (2003)
Dutch	27	70.4	3.7	Semino et al. (2000)
German	16	50.0	6.2	Semino et al. (2000)
Italian central/north	50	62.0	4.0	Semino et al. (2000)
British	~1000		~4	Capelli et al. (2003)
Irish	222	81.5	0.5	Pericic et al. (2005)
Calabrian	37	32.4	0	Semino et al. (2000)
Sardinian	77	22.1		Semino et al. (2000)
British	25	72	0	5
Poles	913			9
Germans	1215			9
Dniester-Carpathian	-		50.06	10
Gagauzes, Kongaz	48		12.5	10

empty or - = no data in sample.
?          = datasets differences, [?-x]:= ^x=# source

• 1 Semino et al. (2000)
• 2 http://www.familytreedna.com/pdf/Levite%20paper.pdf
• 3 http://www.springerlink.com/content/r60m403330h204l0/
• 4 http://www.springerlink.com/content/n2883j06628r5515/
• 9 http://www.springerlink.com/content/w75j6048545350g5/
• 9 http://www.springerlink.com/content/w75j6048545350g5/
• 10 http://edoc.ub.uni-muenchen.de/archive/00005868/01/Varzari_Alexander.pdf
• 11 Capelli et al. 2003, table 1, more data % < 6
• 13 http://mbe.oxfordjournals.org/cgi/reprint/19/7/1008.pdf
• 14 Pericic et al. (2005) + (15'th primary sources?)

[edit] Asia

                             N      R1*    R1a1(%)  Sr. Published
                            
Saharia - Indian Untouchable             72    10     
Ishkashimi                   25      4     68        5 Wells et al. (2001)
Tajiks/Khojant               22      0     64        5 Wells et al. (2001)
Chamar - Indian untouchable                     60

Tajiks/Dushanbe 16 0 19 5 Wells et al. (2001)

Tajiks/Samarkand             40      10    25        5 Wells et al. (2001)
Kyrgyz                       52      2     63        5 Wells et al. (2001)
Southern Altays              96      1     53          V. N. Kharkov et al. (2007)
Tashkent IE                  69      7     47        ?
India Upper Caste            86      -     45.35     8
Sourasthran                  46      0     39        5 Wells et al. (2001)
Abkhazians                   12      8     33        7 Nasidze,2004
Chenchus (India-Drav.)        -      -     26       12  
Kazan Tatar                  38      3     24        5 Wells et al. (2001)
Saami                        23      9     22        5 Wells et al. (2001)
Uyghur                       49     ≤8.2   28.6        Ruixia Zhou et al. (2007)
Dongxiang                    49     <10    28          Wei Wang et al.,2003
Bonan                        47      0     26          Wei Wang et al.,2003
Salar                        52     <10    17          Wei Wang et al.,2003
Iran (Tehran)                24      4      4        5 Wells et al. (2001)
Iran (Tehran)                80      8     20        7 Nasidze,2004 

Iran (Isfahan)               50      0     18        7 Nasidze,2004
Pashtuns                     96      4.2   44.8        Firasat et al. (2007)
Kalash                       44      2.3   18.2        Firasat et al. (2007)
Burusho                      97      1.0   27.8        Firasat et al. (2007)
Pakistan                    638      5.6   37.1        Firasat et al. (2007)
Pakistan  ??                 85      1.10  16.47     8 ?
Pakistan                    175      0.57  24.43     8 ?
Pakistan south               91      0     31.87     8 ?
India                       728      0     15.8      8 ?
India                       325      0.3   27       12 ? 
India (Kashmiri Pandits)      -      -     72.22       Sharma et al. (2007)
Tuvian                       42      2     14        5 Wells et al. (2001)
Abazinians                   14      0     14        7 Nasidze,2004(*7)
Georgians                    77     10     10        7 Nasidze,2004(*7)
Kurd                         17     29     12        5 Wells et al. (2001)
Nenets                       54      4     11        5 Wells et al. (2001)
Syrian                       20     10     10        1

Lebanese                     31     20.0    9.7        Semino et al. (2000)
Turkmen                      21     52.4    4.8        Zerjal et al. (2002)
Turkmen                      30     37      7        5 Wells et al. (2001)
Lezgi(S.Caucasus)            12     17      8        7 Nasidze,2004(*7)
Svans                        25      0      8        7 Nasidze,2004(*7)
Azerbaijanians               72     11      7        7 Nasidze,2004(*7)
Armenians                   100     19      6        7 Nasidze,2004(*7)
Armenians                    47     36      9        5 Wells et al. (2001)
Armenians                   734     32.7    5.0        Weale et al. (2001)
S.Ossetians                  17     12      6        5 Wells et al. (2001)
Kazaks                       54      6      4        5 Wells et al. (2001)
Chechenians                  19      0      5        7 Nasidze,2004(*7)
Kallar Dravidian             84      0      4        5 Wells et al. (2001)
Mongolian                    24      0      4        5 Wells et al. (2001)
Ossetians (Ardon)            28      0      4        7 Nasidze,2004(*7)
Kazbegi                      25      8      4        7 Nasidze,2004(*7)
India Dravidian (Tribal)    180      -      2.78     8 
Kabardinians                 59      2      2        7 Nasidze,2004(*7)
Lezgi(Dagestan)              25      4      0        7 Nasidze,2004(*7)
Ossetians (Digora)           31      0      0        7 Nasidze,2004(*7)
Rutulians                    24      0      0        7 Nasidze,2004(*7)
Darginians                   26      4      0        7 Nasidze,2004(*7)
Ingushians                   22      0      0        7 Nasidze,2004(*7)
Cambodia                      6      0      0        8 ?
China                       127      0      0        8    
Japan                        23      0      0        8
Siberia                      18      0      0        8 ?
                 

Publications:

• (*5) Wells et al. (2001)
• (*6) http://www.journals.uchicago.edu/AJHG/journal/issues/v71n3/023927/023927.web.pdf^{[dead link]}
• (*7) http://www.eva.mpg.de/genetics/pdf/Caucasus_big_paper.pdf^[32]
• (*8) Sengupta et al. (2005) table 5, 6 & 7
• (*12) Kivisild et al. (2003) Fig3 more detailed data for regions, but no caste

[edit] Popular culture

Bryan Sykes in his book Blood of the Isles gives (from his imagination) the populations associated with R1a in Europe the name of Sigurd for a clan patriarch, much as he did for mitochondrial haplogroups in his work The Seven Daughters of Eve.

[edit] See also

• Human Y-chromosome DNA haplogroups
• Genetics and Archaeogenetics of South Asia
• Pole, Hungarian, two good friends
• Y-DNA haplogroups by ethnic groups
• Nordic R1a Y-DNA Project

[edit] Notes

[edit] References

• Bamshad et al. (2001), "Genetic evidence on the origins of Indian caste populations", Genome Research 11(6): 994–1004, PMID 11381027, <http://www.genome.org/cgi/content/full/11/6/994> .
• 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> .
• Kivisild et al. (2003), "The Genetic Heritage of the Earliest Settlers Persists Both in Indian Tribal and Caste Populations", AJHG, <http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=12536373> .
• Mukherjee et al. (2001), "High-resolution analysis of Y-chromosomal polymorphisms reveals signatures of population movements from central Asia and West Asia into India", Journal of Genetics 80(3): 125-135, December, 2001 .
• Passarino et al. (2001), "The 49a,f haplotype 11 is a new marker of the EU19 lineage that traces migrations from northern regions of the black sea", Hum. Immunol. 62(9): 922-932, doi:10.1016/S0198-8859(01)00291-9 .
• 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> .
• Pericic et al. (2005), "High-resolution phylogenetic analysis of southeastern Europe traces major episodes of paternal gene flow among Slavic populations", Mol. Biol. Evol. 22(10): 1964–75, doi:10.1093/molbev/msi185, PMID 15944443, <http://mbe.oxfordjournals.org/cgi/content/full/22/10/1964> .
• Saha et al. (2005), "Genetic affinity among five different population groups in India reflecting a Y-chromosome gene flow", J. Hum. Genet. 50(1): 49–51, PMID 15611834 .
• Semino et al. (2000), "The Genetic Legacy of Paleolithic Homo sapiens sapiens in Extant Europeans: A Y Chromosome Perspective", Science 290: 1155–59, PMID 11073453, <http://hpgl.stanford.edu/publications/Science_2000_v290_p1155.pdf> .
• Sengupta et al. (2005), "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", Am. J. Hum. Genet. 78(2): 202–21, PMID 16400607, <http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1380230> .
• Wells et al. (2001), "The Eurasian Heartland: A continental perspective on Y-chromosome diversity", Proc. Natl. Acad. Sci. U. S. A. 98(18): 10244–9, PMID 11526236, <http://www.pnas.org/cgi/content/full/98/18/10244> .
• Wells, Spencer (2002), The Journey of Man: A Genetic Odyssey, Princeton University Press .
• Oleg Balanovsky Two Sources of the Russian Patrilineal Heritage in Their Eurasian Context

[edit] External links

• Map of R1a
• Spread of R1a1, from the Genographic Project, National Geographic

[edit] Projects

• FTDNA R1a Y-chromosome Haplogroup Project
• R1a International Y-DNA Project
• Danish Demes Regional DNA Project: Y-DNA Haplogroup R1a