Haplogroup R1a (Y-DNA)

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

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.^[2][3][4]. But some studies question these earlier findings and claim that R1a lineages may have its origin in North India ^{[5][6] [7]}. The expansion of R1a has been associated with the spread of the Indo-European languages.^[2][3]

[edit] Origins

European LGM refuges, 20 kya.

The Ukrainian origin of R1a has been independently corroborated by multiple lines of inquiry, including principal component analysis, microsatellite variation, and frequency distribution.^{[citation needed]}

The distribution of R1a resembles the third principal component of variation of classical gene frequencies, whose center of diffusion lies north of the Black and Caspian Seas, which has been attributed to the Kurgan expansion.^[8]

The greater the microsatellite diversity of a haplotype at a particular geographic location, the closer that location is to that haplotype's likely geographic point of origin. In the case of R1a, Semino et al. (2000), Passarino et al. (2001) and Wells (2002) all agree that the highest level of microsatellite diversity is found in Ukraine.

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.)

Spencer Wells, director of the Genographic Project at the National Geographic Society, identifies 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.^[1]

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%).^[3]

Pericic et al. (2005) have suggested three possible scenarios explaining the distribution of R1a:

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.

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.

Passarino et al. (2002) support the first possibility, 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.

Wells et al. (2001) support the second, associating the 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.

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 was magnified by the subsequent expansion of the Kurgan people.

One important observation that has been made about the frequently occurring subgroup R1a1 is that it appears to be very recently introduced in both the western and eastern extremes of its distribution: all the Haplogroup R1a1 Y-chromosomes found among the Czechs of Central Europe and the Khoton people of Mongolia coalesce to a common patrilineal ancestor who should have lived well within the bounds of the Neolithic, and possibly even within the bounds of historical time. The R1a1 component of the Y-chromosome diversity among the Czechs 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.

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

Given the geographic spread and STR diversities of sister clades R1 and R2, the latter of which is restricted to India, Pakistan, Iran, and southern central Asia, it is possible that southern and western Asia were the source for R1 and R1a differentiation.

However, the highest levels of R1 are found in Europe, where frequencies of 70% or more found in populations from Ireland,^[8] Spain,^[2] and the Netherlands,^[2] and where, according to the Genographic Project conducted by the National Geographic Society,^[9] R1 originated on the Iberian Peninsula where, as in Ukraine, there was an LGM refuge from which R1 spread. R1b is, if anything, even more concentrated in Europe than R1.^[8]

[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

Distribution of R1a (purple) and R1b (red), after McDonald (2005). See also this map for distribution in Europe.

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."^[1] 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.^[10]

The modern population of Ukraine has the highest level of diversity of the gene making it the likeliest location of its origin.^[2][11][1] this map^[12] 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)^[12]. 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%),^[13] Hungarians (60.0%),^[2] Poles (56.4%),^[2] , Russians (50.0%)^[14] and Ukrainians (54.0%).^[2] 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.

The last possibility is less probable, the distribution of Paleolithic pattern depth is unexplained by massive people flow. Genetic data support autochtonic school of Slovian historiography.

R1a1 carrying Vikings settled in Britain and Ireland,^[4] which accounts for the presence of the haplogroup on those islands.^[15][16]

[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."^[3] (The frequency of the Tajik/Dushanbe population is, at 19%, far lower than the 64% frequency of the Tajik/Khojant population.)^[3]

The gene has proven to be a "diagnostic Indo-Iranian marker," and "is likely 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".^[3]

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%.^[17] Wells et al. (2001) suggest that the deserts of central Iran acted as "significant barriers to gene flow," and propose two possibilities:

Intriguingly, the population of present-day Iran, speaking a major Indo-European language (Farsi), appears to have had little genetic influence from the M17-carrying Indo-Iranians. It is possible that the pre-Indo-European population of Iran— effectively an eastern extension of the great civilizations of Mesopotamia—may have reached sufficient population densities to have swamped any genetic contribution from a small number of immigrating Indo-Iranians. If so, this may have been a case of language replacement through the ‘‘elite-dominance’’ model. Alternatively, an Indo-Iranian language may have been the lingua franca of the steppe nomads and the surrounding settled populations, facilitating communication between the two. Over time, this language could have become the predominant language in Persia, reinforced and standardized by rulers such as Cyrus the Great and Darius in the mid-first millennium B.C. Whichever model is correct, the Iranians sampled here (from the western part of the country) appear to be more similar genetically to Afro-Asiatic-speaking Middle Eastern populations than they are to Central Asians or Indians.

Noteworthy is as such, result emanate from samples of a few hundred individuals of populations living in non-Iranian inhabited areas.

Haplogroup R1a is also common among Mongolic- and Turkic-speaking populations of Northwestern China, such as the Bonan, Dongxiang, Salar, and Uyghur peoples.^[18][19]

[edit] India

In an important book 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: "and sure enough we find highest rates and greatest diversity of the M17 line in Pakistan, India, and eastern Iran,and low rates in the Caucasus. M17 is not only more diverse in South Asia than in Central Asia but diversity characterizes its presence in isolated tribal groups in the south, thus undermining any theory of M17 as a marker of a 'male Aryan Invasion of India.' Study of the geographical distribution and the diversity of genetic branches and stems again suggests that Ruslan, along with his son M17,arose early in South Asia, somewhere near India..."

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 Brahmins, 2128 Tribals and Dalits) for conclusions. Overall, no consistent difference was observed in Y-haplogroups distribution between Brahmins, Dalits and Tribals, except for some differences confined to a given geographical region. A peculiar observation of highest frequency (up to 72.22%) of Yhaplogroups R1a1* in Brahmins, hinted at its presence as a founder lineage for this caste group. 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*^{[citation needed]}. 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 (Brahmins) and Saharia tribe, and iii) associated averaged phylogenetic ages of R1a* (~18,478 years) and R1a1* (~13,768 years) in India. The study supported the autochthonous origin of R1a1 lineage and a tribal link to Indian Brahmins^{[citation needed]}.

[edit] Haplotypes

[edit] Modal

The Eastern European Y-DNA-R1a Modal Haplotype can be found in Poland, Lithuania, Belorussia 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.^[20] 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^[21]

The Y-DNA sequence is as follows (12 markers):^[22]

Ysearch: YS495

• Tõnu Trubetsky the descendant of Nikita Trubetskoy

Ysearch: WUZG2

• Anderson Cooper also belonged to Y-DNA haplogroup Haplogroup R1a.^[23]

[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	Pericic et al. (2005)
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
Macedonian	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
                            
Ishkashimi                   25      4     68        5 Wells et al. (2001)
Tajiks/Khojant               22            64        5 Wells et al. (2001)
Tajiks/Dushanbe              16            19        5 Wells et al. (2001)
Tajiks (Non-Pamiri)          16            19        5 
Tajiks/Samarkand             40            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 ? 
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     15     10        1

Lebanese                     31     33     20  
Turkmen                      37     36      9          ?
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)
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^[24]
• (*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 fantasy) 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, PMID 15944443, doi:10.1093/molbev/msi185, <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