c Indian Academy of Sciences

RESEARCH ARTICLE

Genetic admixture studies on four in situ evolved, two migrant and twenty-one ethnic populations of , south

G. SUHASINI1,2,3∗, E. SONAA3,S.SHILA3, C. R. SRIKUMARI1, G. JAYARAMAN1 and A. RAMESH1

1Department of Genetics, Dr ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Chennai 600 113, India 2Department of Surgical Gastroenterology, Centre for Gastrointestinal Bleed, Division of Hepato Biliary Pancreatic Diseases and Liver Transplantation, Government Stanley Medical College Hospital, Chennai 600 001, India 3VRR Diagnosis and Research Centre, New No. 87, Burkit Road, T. Nagar, Chennai, India

Abstract We analysed the genetic structure of ∼1000 samples representing 27 ethnic groups settled in Tamil Nadu, , derived from two linguistic families (Dravidians and Indo–Europeans) representing four religious groups (, Islam, Chris- tianity and Jainism) using 11 mtDNA markers. Out of 27 ethnic groups, four are in situ populations (Anglo-Indian, Labbai Muslim, Christian and south Indian Jain) and two are migrants (Gypsy and north Indian Jain) from north India to Tamil Nadu, and 21 are native ethnic groups. Six of the markers we used were monomorphic (HaeIII663, HpaI3592, AluI5176, AluI7025, AluI13262, 9-bp deletion) and five markers were polymorphic (DdeI10394, AluI10397, HinfI12308, HincII13259 and HaeIII16517). Haplogroup frequencies, genetic affinities and admixture analysis are based on the genotype data of poly- morphic markers observed in these populations. Haplogroup frequencies indicate that various ethnic groups entered Tamil Nadu during different time periods. Genetic affinities and admixture estimates revealed that the ethnic groups possessing advanced knowledge of farming cluster in a branch (C), and could be the late arrived settlers as agriculture, was introduced to this region at about 5 to 3 thousand years ago. In situ ethnic groups appear to have arisen at various times as a result of the prevailing dominant socio-cultural forces. Hierarchical Hindu system created many ethnic groups in the history of its existence; some of them became isolated for considerable period of time. Over all, among Tamil ethnic groups, in spite of caste systems’ rigidity, built in flexibility in the system in the form of hypergamy and hypogamy had allowed maternal gene flow between them.

[Suhasini G., Sonaa E., Shila S., Srikumari C. R., Jayaraman G. and Ramesh A. 2011 Genetic admixture studies on four in situ evolved, two migrant and twenty-one ethnic populations of Tamil Nadu, south India. J. Genet. 90, 191–202]

Introduction inhabitants of this state is expected to provide knowledge on some of the early inhabitants of India in general, and Tamil The contemporary populations of India are known to have Nadu in particular. evolved from peopling of India by waves of migrants from Several studies have been conducted on ethnic groups of time to time (Majumder 1998). Therefore, an intensive study Tamil Nadu that varied in the socio-cultural order, using of Indian populations provide deep knowledge about evo- somatoscopic, somatometric and genetic markers (Sanghvi lutionary forces that may be responsible for the diversity and Balakrishnan 1981), DNA markers (Wells et al. 2001; of contemporary Indian populations. The north Indian pop- Basu et al. 2003; Sitalaxmi et al. 2003; Rajkumar et al. 2004; ulations are predominantly Indo–European language speak- Kashyap et al. 2006; Kanthimathi et al. 2007; Vijaya et al. ers and south Indian populations are Dravidian speakers 2007) and HLA class II polymorphic markers (Pitchappan (Meenakshi 1995). Among these two linguistic groups, Dra- 2002). These studies revealed that many of them were mi- vidian language speakers are considered to be more ancient grants to Tamil Nadu from the neighbouring regions and that (Gadgil et al. 1998). Since Tamil Nadu in south India is the state harbours people who travelled by southern route from an ancient seat of Dravidian culture, focussed study on the Africa. The phylogenetic analysis placed them in a cluster, away from Indo–European speakers (Forster and Matsumura ∗ For correspondence. E-mail: [email protected]. 2005; Kanthimathi et al. 2007). Molecular evidence indicates Keywords. Dravidian; mitochondrial DNA; admixture; south India; human genetics.

Journal of Genetics, Vol. 90, No. 2, August 2011 191 G. Suhasini et al. that mtDNA haplogroups M1 and M3 are found on the (ANI) and ancestral south Indian (ASI) gene pool. We have Horn of Africa, Arabia/Yemen, and Iran along a migration also tried to explain the same through our work. Histor- path to south India, which is congruent with anthropological, ically, hypogamy has not been encouraged. On the other linguistic and archaeological evidence and suggest African hand, in hypergamy women can adopt the caste and social origin for the Dravidian speakers (Winters 2008). Sanghvi status of the men whom they marry (Bhattacharyya et al. et al. (1981) even identified the ethnic groups of Tamil Nadu: 1999). Therefore, examining the female lineages could help Chakkiliyar, Parayan and Mutracha (Ambalakarar) as the in delineating the genetic structure of the ethnic groups most ancient who belong to the Paleolithic period. better. The genetic structure of the Tamil Nadu populations can To know the genetic structure (genomic affinities and be inferred from both matrilocal and patrilocal studies, as mi- interethnic admixture) of ethnic groups settled at various gration is gender based. Even though the caste system is rigid, time periods in Tamil Nadu, we analysed the maternal lin- two social rules viz., hypergamy or ‘Anuloma’ (a woman eage of 21 ethnic groups of this region and six more Tamil marrying a man of higher social rank) and hypogamy or ethnic groups studied by Basu et al. (2003) which could be ‘Pratiloma’ (a woman marrying a man of lower social sta- grouped variously based on religion, socio-economic rank- tus) provides flexibility to the rigid caste system. Reich ing in the caste hierarchical structure of the Hindu religion, et al. (2009) tried to point out the admixture in the Indian past traditional occupation, geographical origin and known population beyond the endogamy of ancestral north Indian in situ evolution (table 1).

Table 1. Ethnological information on the study populations.

Linguistic Categories Population name N Social strata group Traditional occupation/remarks

A. Non-Hindu populations Migrant a) Jain North Indian Jain (NJ) 37 IE Trade/money lending/commerce In situ a) Jain South Indian Jain (SJ) 50 DR Agriculture/trade b) Christian Anglo-Indian (AI) 38 IE Urban dwellers Nadar Christian (NC) 46 DR Trade/agriculture/toddy tapping c) Muslim Labbai Muslim (ML) 50 DR Trade B. Hindu populations Migrant Gypsy (GP) 44 Low rank IE Seminomadic, denotified community, hunters, urban dwellers (IYN) 30 Upper rank DR Priests/scholars Iyer (IYR) 30 Upper rank DR Priests/scholars NonBrahmins a) Vellalar Agamudaiya Vellalar (AV) 47 Mid rank DR Agriculture Kongu Vellala Gounder (KG) 54 Mid rank DR Thuluva Vellalar (TV) 51 Mid rank DR Veerakodi Vellalar (VLR) 43 Mid rank DR b) Scheduled Chakkiliyar (CH) 45 Low rank DR Formerly untouchable leather workers, Agricultural labourer Pallan (PLN) 30 Low rank DR Agriculture Parayan (PA) 50 Low rank DR Agricultural labourer Common origin c) Thevar Agamudaiyar (AR) 47 Mid rank DR Agriculture Kallar (KL) 50 Mid rank DR Agriculture (MR) 45 Mid rank DR Agriculture d) Others Ambalakarar (AMB) 30 Mid rank DR Village heads Gavara Naidu (GN) 33 Mid rank DR Trade/agriculture Meenavar (MV) 68 Mid rank DR Fishermen (coastal) Nadar Hindu (NH) 51 Mid rank DR Agriculture/trade/toddy tapping Nattukkottai Chettiar (NK) 44 High rank DR Trade/commerce Reddiyar (RY) 49 Mid rank DR Agriculture Sengundar Mudaliar (SM) 50 Mid rank DR Weavers (VAN) 30 Mid rank DR Agriculture/trade Yadavar (YR) 51 Mid rank DR Animal husbandry/agriculture

IE, Indo European; DR, Dravidian.

192 Journal of Genetics, Vol. 90, No. 2, August 2011 Genetic structure of Tamil Nadu ethnic groups

Methods While estimating the admixture in in situ and migrant pop- ulations, these populations are considered as hybrid (Ph) and Populations the 21 ethnic groups as parental populations. Similarly, in A total of 1000 genomic DNA belonging to 21 ethnic groups case of estimating admixture in 21 ethnic groups, each time (three Indo–European language speaking groups: Anglo- one population among the 21 is considered to be hybrid and Indian, Gypsy and north Indian Jain; and 18 Tamil ethnic other 20 as parental population. groups: Muslim Labbai, south Indian Jain, Nattukkottai Chettiar, Sengundar Mudaliar, Agamudaiya Vellalar, Thuluva Vellalar, Yadavar, Kallar, Maravar, Agamudaiyar, Kongu Vellala Gounder, Nadar Hindu, Nadar Christian, Meenavar, Gavara Naidu, Reddiyar, Parayan and Chakkiliyar) were screened for mtDNA variations. Six more Tamil ethnic groups studied by Basu et al. (2003) were also included for phylogenetic and admixture analysis. These include: Iyer, Iyengar, Vanniyar, Ambalakarar, Veerakodi Vellalar and Pal- lan. A brief ethnographic information on all these ethnic groups is given in table 1.

Genetic markers DNA samples were screened for 11 coding region variations Since there would be too many combinations, one popu- in mtDNA (HaeIII np 663, HpaI np 3592, AluI np 5176, AluI lation was always designated as common parental popula- np 7025, DdeI np 10394, AluI np 10397, HinfI np 12308, tion (P ). Thus, we have estimates of admixture proportions HincII np 13259, AluI np 13262, HaeIII np 16517 and 9- n for the n–1 populations. Individual admixture proportions of bp deletion; Torroni et al. 1993, 1996) to infer the gene these n–1 populations were pooled and a single estimate of flow between the Dravidians and contribution from different admixture proportion was estimated for the common parental groups of immigrants to Dravidians. population (Pn) paired with the remaining n–1 populations. Since for each pair of parental populations, p1 + p2 = 1, Statistical analysis the contribution for any hybrid population by n number of populations have to be adjusted to 1. This is done, by adding Haploid allele frequencies (mtDNA) were computed by admixture estimates of each population and then adjusting the gene counting method. Haplotype and haplogroup them to 1, as relative contribution to the hybrid population. frequencies based on 11 loci observed were estimated Values of the populations, thus obtained if less than one per using Arlequin 3.1 software (Excoffier et al. 2005;see cent is considered to be none contributing. tables 1 & 2 in electronic supplementary material at http:// www.ias.ac.in/jgenet). Average heterozygosity at five polymorphic loci (DdeI10394, AluI10397, Hinf I12308, Results and discussion HincII13259 and HaeIII16517) for each population was estimated using DISPAN software (http://www.bio.psu.edu/ Mitochondrial DNA lineages in Tamil ethnic groups people/faculty/Nei/Lab/dispan2.htm). This software also cal- In our study, the mtDNA restriction sites: HaeIII663 (pres- culates gene diversity (Nei 1973), genetic distance between ence denotes haplogroup A), HpaI3592 (presence denotes the populations (Nei 1987) and constructs phylogenetic haplogroup L), AluI13262 (absence denotes haplogroup C) tree by neighbour-joining (NJ) method using the haplotype and the 9-bp deletion (haplogroup B) were monomorphic for frequencies (Ota 1993). their ‘absence’; and AluI-5176 (absence denotes haplogroup Admixtures of four in situ populations (Anglo-Indian, D) and AluI7025 (absence denotes haplogroup H) restriction Labbai Muslim, Nadar Christian and south Indian Jain) sites were fixed in all populations. The remaining five loci: and two migrant populations (Gypsy and north Indian Jain) DdeI10394 and AluI10397 (presence denotes haplogroup M with the 21 ethnic groups of Tamil Nadu, south India; and and absence denotes haplogroup N), Hinf I-12308 (presence within the 21 ethnic groups were analysed using LEAD- denotes haplogroup U), HincII13259 (absence denotes hap- MIX software (Wang 2003) based on haplotype frequen- logroup C) and HaeIII16517 (presence denotes haplogroup cies. LEADMIX performs maximum likelihood estimation F) were polymorphic. of admixture proportions in a model where the ancestral population (P ) is split into two parental populations P and 0 1 Haplogroup M and N P2 that evolved independently before they contributed in genetic proportion p1 and p2 (where, p2 = 1 − p1) to form The early settlers: The South Asian specific haplogroup M, a hybrid population (Ph). arose before the split of proto-Indians and proto-Orientals

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Table 2. Frequencies (%) of mtDNA haplogroups in ethnic popu- elements. In this study, haplogroup N varied in range from 5 lations of Tamil Nadu. to 42 per cent (table 2). The average frequency of this hap- logroup is 25 per cent. High frequency was observed among Haplogroups Agamudaiya Vellalar (40.4%), Kongu Vellala Gounder Populations M (%) N (%) U (%) F (%) (40%), Maravar (41.20%), Reddiyar (36.7%), north Indian Jain (34%) and Thuluva Vellalar (33.4%). It is less frequent AI 27 (71.0) 10 (26.3) 1 (2.60) 0 (0.00) ≤ AV 23 (48.9) 19 (40.4) 3 (6.40) 2 (4.30) ( 14%) in ethnic groups who have high values of hap- AR 40 (85.1) 4 (8.5) 3 (6.30) 0 (0.00) logroup M. Probably, these ethnic groups arrived later than CH 43 (95.5) 2 (4.5) 0 (0.00) 0 (0.00) the ethnic groups having higher frequencies of haplogroup GN 21 (63.7) 5 (15.2) 6 (18.20) 1 (3.00) M and may be admixed with Caucasoid elements. The in GP 27 (61.4) 8 (18.2) 8 (18.30) 1 (2.30) situ evolved Anglo-Indians are expected to have higher KG 23 (46.0) 20 (40.0) 5 (10.00) 2 (4.00) KL 35 (64.8) 14 (25.9) 3 (5.60) 2 (3.70) frequency of haplogroup N in view of their known Caucasian ML 30 (66.6) 9 (20.0) 6 (13.30) 0 (0.00) parentage in early times of their evolution. However, its fre- MR 33 (48.5) 28 (41.2) 2 (3.00) 5 (7.30) quency about 26 per cent is even much below the values MV 40 (80.0) 7 (14.0) 3 (6.00) 0 (0.00) observed in some ethnic castes of this study. This low fre- NC 27 (58.7) 7 (15.2) 12 (26.10) 0 (0.00) quency could be due to small contribution of the founder NH 37 (72.6) 10 (19.6) 3 (5.90) 1 (2.00) NJ 22 (49.9) 15 (34.0) 6 (13.70) 1 (2.30) female Caucasoids in comparison to male and the resultant NK 14 (37.8) 13 (35.2) 9 (24.30) 1 (2.70) hybrids probably being married back to the ethnic groups that PA 36 (72.0) 10 (20.0) 3 (6.00) 1 (2.00) have higher frequency of haplogroup M. RY 21 (42.8) 18 (36.7) 7 (14.20) 3 (6.10) SJ 39 (78.0) 11 (22.0) 0 (0.00) 0 (0.00) SM 37 (74.0) 7 (14.0) 5 (10.00) 1 (2.00) The scheduled castes versus other ethnic groups: The hap- TV 25 (49.0) 17 (33.4) 8 (15.70) 1 (2.00) logroup M was below the average frequency (63%) in YR 27 (52.9) 14 (27.50) 7 (13.80) 3 (5.90) Vellalars (Agamudaiya Vellalar, Kongu Vellala Gounder and Total 627 (62.7) 248(24.8) 100 (10) 25 (2.5) Thuluva Vellalar), Maravar, north Indian Jain, Nattukkottai Chettiar and Reddiyar (≤ 50%). High values (≥ 72%) were observed in schedule caste populations (Chakkiliyar, Pallan and predated the entry of Indo–Aryans into India (Passarino and Parayan; table 2). This means that schedule caste popu- et al. 1996). This haplogroup, in the present study, varied lations could be the older inhabitants of this region than the in range from 38 per cent (Nattukkottai Chettiar) to 96 per former. These results are consistent with an earlier study on cent (Chakkiliyar; table 2). Agamudaiyar, Meenavar, Nadar anthropometric variation of Tamil ethnic groups (Malhotra Hindu, Parayan, Sengundar Mudaliar also possessed very et al. 1981). This study includes some of the present study high values of haplogroup M (≥ 72%). populations. They observed that proto-Australoids, being The high frequency of haplogroup M in Chakkiliyar indi- darkest, are the oldest and might have lived in this region cates that it could be one of the oldest populations. Four pre- 20 to 15 thousand years ago (kya). According to them, these viously studied populations also showed a frequency greater anthropometric elements are present in scheduled castes than 90 per cent for this haplogroup (Ambalakarar, 90%; (Chakkiliyar and Parayan) and in some low rank populations West Bengal Brahmins, 90%; Kota, 96.7%; Toto, 96.67%; (Mutracha). Roychoudhury et al. 2000;Edwinet al. 2002;Basuet al. 2003). Among these four populations, Ambalakarar and Kota Subdivision by religion—Nadar Hindu and Nadar Christian: belong to Tamil Nadu, Toto and West Bengal Brahmins The religious subdivision of Nadars is expected to bring belong to West Bengal. Numerically, the Kota and Toto are some differentiation between them. Large scale conversion very small in number around 1000 individuals each. Very to Christianity dates to about 200 years ago (Singh 1997). high frequency of haplogroup M in both these tribes could Conversion to Christianity allowed admixture with other eth- be due to their small size. Overall, in this study, about 63 per nic groups at greater pace than would have been possible. cent of the individuals possessed haplogroup M. This is con- The haplogroup M was less frequent in Nadar Christian sistent with the earlier published data (Anderson et al. 1981; (59%) than in Nadar Hindu (73%; table 2). This suggests Passarino et al. 1996; Barnabas et al. 2000; Roychoudhury that Nadar Christians admixed more with the ethnic popula- et al. 2000;Edwinet al. 2002;Basuet al. 2003). The in situ tions that had less frequency of haplogroup M (Agamudaiya evolved populations have frequencies comparable with the Vellalar, Kongu Vellala Gounder, Maravar, Reddiyar, Thuluva ancient ethnic groups. Vellalar and Yadavar).

Caucasoid element among Tamil ethnic populations: The hap- Common ancestry of Thevar groups—Agamudaiyar, Kallar and logroup N is considered to be a pan-Caucasian marker Maravar: The Thevar groups consider themselves to have (Roychoudhury et al. 2000). Its presence in Tamil ethnic a common ancestry (Singh 1997). They showed substantial groups could imply an admixture of Caucasian (Indo–Aryan) variation in the frequency of haplogroup M (Agamudaiyar,

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85%; Kallar, 65%; Maravar, 49%; table 2). This diversity Genetic distance and affinities could be accounted to unequal splitting and admixture with Gene diversity: The gene differentiation between the 21 Tamil the late arrived ethnic groups and who may have high fre- ethnic groups (G ) is 7.62 per cent (P < 0.005) and increases quencies of haplogroup N. st to 8.24 per cent (P < 0.005) with the inclusion of six Tamil ethnic groups from an earlier study of Basu et al. (2003) Haplogroup B (see tables 2 & 3 in electronic supplementary material). No change in Gst was observed if the migrant and in situ eth- The African foot prints in Tamil ethnic groups: The9-bpdele- nic groups were excluded (8.53; P < 0.005). The migrant tion marker (location np 8272 – np 8289) arose in cen- and in situ ethnic groups themselves have a lower G value, tral Asia on -/- background (DdeI-10394 and AluI-10397; st 5.76 per cent (P < 0.005). The variation in the magnitude Haplogroup B) and is reported to have migrated to parts of of gene differentiation among the different groups analysed southeast Asia (Ballinger et al. 1992). This marker is absent could be due to their inherent diversity. in all the studied ethnic groups. Thus, there is least possibility of Tamil ethnic groups being descendants of central/southern China migrants. Genetic affinities: The genomic affinities revealed by the unrooted NJ tree highlighted some features (see figure 1). The 27 ethnic populations aligned neatly into two branches Haplogroup U (C and D) that signify broad cultural division existing among The west Eurasian marker: Presence of HinfI-12308 restric- them. The ‘most ancient’ populations clustered in one branch tion site with -/- background (DdeI-10394 and AluI-10397) (D), whereas the ‘culturally most advanced’ ethnic groups was designated as haplogroup U. Its presence is considered clustered in another branch (C). to be a west Eurasian marker and its absence in the context of India implies lack of admixture with the Indo–Aryan ethnic groups (Roychoudhury et al. 2000). Overall, this haplogroup accounts for about 10 per cent of the individuals genotyped. Roychoudhury et al. (2000) reported an overall frequency of 14.28 per cent for this haplogroup among Indian populations. In Europeans, the average frequency of this haplogroup is about 25 per cent (http://www.mitomap.org/cgi-bin/tbl5gen. pl). High values (≥ 15%) have been found in Gavara Naidu, Gypsy, Nadar Christian, Nattukkottai Chettiar and Thuluva Vellalar (table 2). This indicates probable contribution of west Eurasians to these populations. In Chakkiliyar and south Indian Jain, this haplogroup is absent.

Haplogroup F The southeast Asian haplogroup: The southeast Asian Hap- logroup F is characterized by the presence of HaeIII- 16517 and absence of HincII-12406 restriction sites in -/- background (DdeI-10394 and AluI-10397). This haplogroup accounts for over 25 per cent of the southeast Asians. Its presence in the Indian population means contribution by Sino Tibetan language speakers during their expansion around 6 to 8 kya (https://www3.nationalgeographic.com/genographic/ atlas.html?card=mm017). This haplogroup is absent in all in situ populations and in Agamudaiyar, Meenavar and Chakkiliyar. In the remaining populations, its frequency var- ied from ∼2 to 8 per cent (table 2). This haplogroup is mostly found in the northeast Indian tribes (∼16%; Cordaux et al. 2003), Andamanese (10%) and Nicobarese (50%; Thangaraj et al. 2003), Vietnamese (32%) and Chinese (10.8%; Tolk Figure 1. Neighbour-joining tree of 27 ethnic populations based et al. 2001). In this study, values closer to 8 per cent were on mtDNA haplotype. Nomenclature of the NJ tree, A and B, ances- tral and derived node; C and D, branch; C1, C2, D1 and D2 - found in Maravar (7.3%), Reddiyar (6.1%) and Yadavar sub-branch; C1a, C2a, D1a, D1b and D2a, clade; C1a1, D1a1, (5.9%). Therefore, it could be inferred that the Tamil ethnic D1b1, D1b2 and D2a1, subclade; C1a1.1, C1a1.2, D1a1.1, D1b1.1 groups had experienced some gene flow from southeast Asia. and D1b2.1, cluster; C1a1.11, C1a1.21 and D1b1.11, subcluster.

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Cultural gradient: Kallar, Maravar, Parayan, Agamudaiyar, the Tamil ethnic groups or among themselves. The entry of Chakkiliyar, Pallan, Ambalakarar and Meenavar who occupy Europeans into India dates to the period of 15th to 18th cen- lower social strata among nonBrahmins and are culturally less tury AD (Richards 1997). The Caucasian heredity among advanced cluster on branch D. Kallar, Parayan, Chakkiliyar Anglo-Indians might have been diluted. They are placed and Ambalakarar (Mutracha) could have settled in this region closer towards the low-rank Indian ethnic groups. about 20 to 10 kya (Malhotra et al. 1981). This means that Muslim Labbai (Sunni) are believed to be either converts culturally less advanced may be the early settlers. This clus- from Hindu castes or born out of marital relationship between tering is consistent with the findings of Undevia et al. (1981) immigrant Muslim and natives (Singh 1997). Kivisild et al. who also analysed the genetic affinities of Tamil ethnic (2003) and Terreros et al. (2007) in their studies observed groups using classical genetic markers. According to them, that Sunni Muslims are mostly descendants of Hindu con- low rank nonBrahmins (like Vanniyar, Kallar and Mutracha verts. Islam has substantial influence all over the Indian sub- or Ambalakarar) are closely affiliated with the Harijans continent. They found the near-east mtDNA haplogroup R— (Parayan and Chakkiliyar), whereas Kongu Vellala Gounder, which is common among Indians, in Indian Sunni Muslims Thuluva Vellalar, Reddiyar and Agamudaiya Vellalar who also. Muslim Labbai showed closer affinity with are traditional agriculturists and occupy higher social strata groups. Jasti et al. (2008) who analysed the genetic affini- among nonBrahmins were clustered in branch C (figure 1). ties of two south Indian Brahmin groups and Sunni Muslims Agriculture was introduced to this region about 3 kya using HLA class II (DRB1) observe that Muslims might have (Cavalli-Sforza et al. 1994) and they could be considered as been the result of admixture between Indo–Europeans and ‘late’ arrived settlers with advanced skills in farming. proto-Dravidians. On the other hand, Brahmins are consid- ered to possess Caucasian elements and migrant to south India (Mahadevan 2008). This suggests a shared heredity Exceptional features of branch D: Iyer and Iyengar (Brahmins, priestly communities), Nattukkottai Chettiar (trading com- between Muslim Labbai and Brahmins. munity) and Veerakodi Vellalar (traditional agriculturist com- munity) clustered with the lower strata nonBrahmin groups. Migrants: The migrant populations from northwest India— north Indian Jain and Gypsy clustered along with the sub- clade, C1a1. North Indian Jain (trading community) formed a Exceptional features of branch C: The Nadars (toddy tap- close cluster with Kongu Vellala Gounder (agriculture com- pers and traders), Gavara Naidu (agriculturists and traders), munity). The Gypsy (semi nomadic community) formed a Vanniyar (equivalent to of north India) and close cluster with Nadar Hindu (toddy trappers and traders). Yadavar (animal husbandry and agriculture) cluster along Their relations are unexpected and cannot be explained with with traditional agriculture ethnic groups. the known ethno histories of the groups.

In situ populations: Nadar Christians cluster with relatively Genomic affinities of branch D ethnic groups: The Chakkiliyar advanced ethnic groups of branch C, whereas Anglo-Indian, (Harijans) and Agamudaiyar (low rank nonBrahmin) formed south Indian Jain and Muslim Labbai cluster with more a deep rooted cluster. This unexpected relationship remained ancient ethnic groups of branch D. This could be due to their unchanged even with the removal of in situ and migrant variation in origin. Nadar Christian are considered to have groups. The close relationship observed in this study could be split from Nadar Hindu some 200 years ago (Singh 1997), explained only by assuming shared ancestry. Malhotra et al. probably admixed with the Christians of other ethnic groups. (1981) observed that Chakkiliyar could be the early settlers The branch D in situ populations showed a pattern of clus- ofTamilNadudatingto20kya. tering which depicts their ancestry and origin. The south The Sengundar Mudaliar (weaver community), Parayan Indian Jains are the earliest in situ ethnic group to have orig- (Harijans) and Meenavar (marine fisherfolk) formed inde- inated during 3rd century BC, when a well defined caste pendent clusters in subclade, D1b1 and are closer with the system did not exist (Singh 1997). They formed a close Chakkiliyar and Agamudaiyar who formed a close cluster cluster with Ambalakarar (Mutracha) and, together with in the same subclade. Closer affinity between Meenavar and Anglo-Indians, formed a subclade, D1b2. This subclade with Parayan was observed in an earlier study of Kanthimathi subclade D1b1 that consists of early settlers (Agamudaiyar, et al. (2008) who used autosomal markers. In another study, Chakkiliyar, Meenavar, Parayan and Sengundar Mudaliar) both Chakkiliyar and Parayan were reported to have proto- formed a clade, D1b (figure 1). Conversion into Jainism from Australoid racial elements (Malhotra et al. 1981). The close among these early settlers and subsequent inbreeding might genetic affinities between Parayan, Meenavar and Chakkiliyar be responsible for the evolution of south Indian Jain. could arise if they share a common ancestral group. Like- Anglo-Indians, initially originated as a result of rela- wise, all the ethnic groups of subclade, D1b1 could have had tionships between immigrant Europeans and Indian ethnic a common ancestor. groups (Thurston 1975), especially those occupying lower The close genetic affinity between the two Brahmin groups: strata of the society. In subsequent generations, the first gen- Iyer and Iyengar might be due to the well known fact that eration hybrids might have maintained relations more with the latter arose from the former as a split group during

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12th century (Sanghvi and Balakrishnan 1981). Brahmin Kongu Vellala Gounder, Thuluva Vellalar, Agamudaiya groups, along with Muslim Labbai and Nattukkottai Chettiar Vellalar were placed in branch C and Veerakodi Vellalar formed a subbranch, D2. Their affinity with other groups of alone were placed in branch D. Vellalars, Brahmins, Mudaliar, branch D indicates a possible flow of heredity from the lat- Chettiar and Naidu possess Western brachycephalic racial ter. This is not surprising if one considers the ‘Anuloma’ and elements (Malhotra et al. 1981) and therefore, expected to ‘Pratiloma’ exceptions to the theoretically rigid Hindu reli- cluster in one branch. Veerakodi Vellalar being placed in gious caste/subcaste endogamy. These exceptions allow the different branch could be due to differential gene flow. gene flow from castes of lower status to the castes of higher status and vice-versa (Sanghvi and Balakrishnan 1981; Admixture analysis Balakrishnan et al. 1996). Historically, ‘Pratiloma’ has been Admixture analysis is expected to shed more light on inter- discouraged and men rarely cross caste boundaries. Women relationships of the ethnic groups. An equitable exchange were allowed to adopt the caste and social status of the men between populations refers to the absence of social processes whom they marry (Bhattacharyya et al. 1999). The interme- that inhibit biological exchange of genes, likewise in reverse, diate position of Brahmins (Iyer and Iyengar) between sub- gene flow between ethnic groups implies the existence of branch D1 and branch C indicate sharing of their heredity social restrictions and an unequal exchange means greater with the populations of these two extreme groups. Ethnic influence of highly contributing population. Through admix- groups like Mudaliar, Vellalar, Chettiar, Brahmin and Naidus ture analysis one could find out which of the 21 native ethnic possess Western branchycephalic racial elements and they groups contributed to the evolution of in situ populations and might have entered the region at least 5 to 3 kya (Malhotra the extent to which the migrant populations absorbed genes et al. 1981). from the natives (table 3). TheThevargroupsorMukkulathor: Agamudaiyar, Maravar In situ populations: admixture by Tamil speaking ethnic and Kallar were found in different subclades of branch populations D. Maravar formed a close cluster with Veerakodi Vellalar (figure 1, D1a1.1). They are one among the Vellalar groups South Indian Jains, Muslim Labbai, Nadar Christians and and their main occupation is agriculture (Singh 1997). Kallar Anglo-Indian have evolved in situ when one or other formed a close cluster with them. Pallan formed a separate religion predominantly patronized by the ruling class at dif- cluster in clade D1a. Among them, Kallar were reported ferent periods in the history of the Indian subcontinent. to possess Mediterranean racial elements and said to have The contribution of mitochondrial genes by the 21 Tamil migrated into this region some 10 kya (Malhotra et al. 1981). Maravar are considered to be a subdivision of Kallar Table 3. Admixture proportion of in situ and migrant populations (Thurston 1975). Pallan an agricultural community ranks based on mtDNA polymorphic markers. highest among scheduled castes (Ramaiah 2004;Censusof India 2001). Maravar forming a close cluster with Veerakodi Hybrid Vellalar rather than with Kallar is surprising. Likewise, In situ Migrant Pallan clustering with these populations rather than with Parental SJ NC ML AI NJ GP other scheduled caste populations is unexpected. The genetic affinities of Thevar groups could be explained partly by AV 0.0005 0.0857 0.0521 0.0710 0.0519 0.0811 geographical expansion, split and admixture with diverse AMB 0.1045 0.0001 0.0154 0.0052 0.0153 0.0173 neighbourhood groups. AR 0.0008 0.0002 0.0003 0.0003 0.0003 0.0037 CH 0.0942 0.0001 0.0001 0.0002 0.0001 0.0002 GN 0.0003 0.0403 0.0003 0.0003 0.0003 0.0814 Genomic affinities of branch C ethnic groups: Yadavar showed IYN 0.0003 0.0088 0.0919 0.1521 0.0914 0.0814 closer affinity with Vanniyar. They inturn, cluster with IYR 0.0003 0.0863 0.0347 0.0002 0.0346 0.0023 Agamudaiya Vellalar to form a subbranch C2 (figure 1). KG 0.0003 0.0862 0.0290 0.1672 0.0289 0.0812 KL 0.2390 0.0643 0.1386 0.1687 0.1379 0.0814 Wells et al. (2001) reported that Yadavar of , south MR 0.0020 0.0002 0.0260 0.0019 0.0259 0.0001 India, have haplogroup J2 derived from haplogroup J of Y MV 0.0168 0.0863 0.0003 0.0052 0.0003 0.0814 chromosome about 10 kya. Haplogroup J2 represents the NH 0.0659 0.0863 0.0001 0.0552 0.0001 0.0814 agricultural innovators who followed the rainfall (Chiaroni NK 0.0003 0.0682 0.0261 0.0003 0.0260 0.0001 et al. 2008), and is more frequent among Mediterraneans PLN 0.0158 0.0649 0.1162 0.1644 0.1156 0.0813 RY 0.0003 0.0863 0.0367 0.0002 0.0365 0.0814 (Semino et al. 2004). This shows that the ancestors of SM 0.1463 0.0631 0.1312 0.0078 0.1305 0.0813 Yadavar might have entered India 10 kya or even earlier and TV 0.0003 0.0863 0.0609 0.0078 0.0655 0.0814 later entered the Tamil speaking region. Their close affin- VAN 0.0000 0.0863 0.0869 0.0858 0.0864 0.0814 ity with Vanniyar who possess paleo-Mediterranean racial VLR 0.0626 0.0001 0.0835 0.1056 0.0831 0.0001 elements (Malhotra et al. 1981) could be due to shared YR 0.0003 0.0001 0.0692 0.0003 0.0689 0.0001 PA 0.2497 0.0002 0.0005 0.0003 0.0005 0.0002 heredity, and close relationship with Agamudaiya Vellalar Total 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 could be due to admixture.

Journal of Genetics, Vol. 90, No. 2, August 2011 197 G. Suhasini et al. speaking ethnic groups to the evolution of four in situ differing culture. North Indian Jain belongs to the Svetam- populations are presented in table 3. bar sect of Jainism settled all over India in almost all impor- South Indian Jain belongs to Digambar sect of Jainism. tant urban areas and work as money lenders, traders and During 3rd or 4th century AD, Jainism and Buddhism ex- industrialists. They trace their origin to northwest India. Gyp- isted side by side with Brahmanism when there was no sys live as nomads on urban pavements, semiurban and in Saivism or (Singh 1997). Parayan, Kallar, urban peripheral areas (Singh 1997). North Indian Jain re- Sengundar Mudaliar, Ambalakarar, Chakkiliyar, Veerakodi ceived mitochondrial genes more from branch D populations Vellalar, Meenavar and Pallan contributed about 93 per (∼66%) than from branch C populations (∼34%). None of cent of the admixed genes. Brahmins, Vanniyar, Chettiar, the early settlers (Chakkiliyar, Parayan, Ambalakarar and Yadavar, Reddiyar, Gavara Naidu and Vellalars (excluding Meenavar) did contribute to them. This is in contrast to the Veerakodi Vellalar) have not contributed to the south Indian observations made in south Indian Jain. This implies that Jains. It is obvious that Jainism as a religion had tremen- the north Indian Jains were not responsible for the origin dous influence on early settlers and least influence on late and evolution of south Indian Jain. Branch C ethnic groups arrived migrants. A significant observation is that, the two (excluding Yadavar; ∼56%) contribution to Gypsy is greater scheduled caste populations viz., Parayan and Chakkiliyar than those of branch D (∼42%) ethnic groups. Chakkiliyar, contributed exclusively to the south Indian Jain but not to Parayan, Ambalakarar, Nattukkottai Chettiar, Iyer and Maravar the other in situ populations. Iyengar, Pallan, Kallar and of branch D did not contribute to Gypsy. Veerakodi Vellalar of branch D together account for about 2/3rd of the Anglo-Indians’ admixed mitochondrial genes. Socio-economic groups-admixture with other Tamil ethnic groups Kongu Vellala Gounder, Nadar Hindu, Agamudaiya Vellalar and Vanniyar of branch C accounted for the remaining 1/3rd Scheduled castes: Scheduled castes (Chakkiliyar, Parayan and of the admixed mitochondrial genes. Thus, both early and Pallan) also collectively known as ‘’ or ‘Harijans’, late arrived settlers contributed to the evolution of Anglo- were treated as ‘untouchables’ by other ethnic groups for Indians. Fifteen ethnic groups contributed to the Muslim substantial part of their evolution. Pallan and Chakkiliyar Labbai. This reflects larger influence of Islam over the Indian occupy the highest and lowest status among them, respec- subcontinent even though it arrived as late as 12th cen- tively (Census of India 2001). Chakkiliyar and Parayan tury (Thurston 1975). However, Chakkiliyar, Agamudaiyar, are known to possess proto-Australoid elements (Malhotra Meenavar, Parayan, Nadars and Gavara Naidu have not con- et al. 1981). Chakkiliyar had no exchange of mitochondrial tributed to Muslim Labbai. It means that Islam as a religion genes with 15 ethnic groups. Even with those they have has little or no influence on early settlers. exchanged, the exchange is always unequal. They received It is surprising to note that the magnitude of contribu- far more than they could contribute. Pallan contributed sub- tion by Nadar Hindu is of comparable magnitude with the stantially but did not receive genes from the Chakkiliyar. contributions of some seven other populations (Agamudaiya Though Chakkiliyar and Parayan showed substantial differ- Vellalar, Kongu Vellala Gounder, Iyer, Meenavar, Reddiyar, ence in admixture they had with other ethnic groups, the for- Thuluva Vellalar and Vanniyar) when one expects a larger mer is almost ‘isolated’ while the latter exchanged, fairly contribution due to their reported large scale conversion with a large number of ethnic groups. This is largely due to into Christianity during 16th to 19th century (Cavalli-Sforza menial jobs that were assigned to Chakkiliyars by the soci- et al. 1994). The Nadar Christian might have evolved by ety at large. Pallan who occupy the highest status among the initial split from Nadar Hindu and subsequent admixture scheduled castes and reasonably well advanced in farming with other similarly converted ethnic groups who might have (Singh 1997) contributed mitochondrial genes to all the eth- given up ethnic identity perhaps due to their conversion nic groups and also had equitable exchange with Kallar, one in smaller numbers over a longer period. Branch C ethnic of the ancient populations settled in Tamil region about 10 groups contribution is much greater (∼58%) than those of kya (Wells et al. 2001). branch D (∼38%). Overall, Christianity has less influence on early settlers than on the late arrived ethnic groups. These Thevars or Mukkulathors: Agamudaiyar, Kallar and Maravar infer that south Indian Jain was the earliest among in situ also known as Thevars, consider themselves to be originat- populations. Anglo-Indians could have arisen next to them. ed from common ancestor. In the NJ tree they were placed Nadar Christian, as known today originated later to Anglo- in separate clades of subbranch D1. Kallar and Maravar Indians; and the Muslim Labbai originated earlier to the were placed in one clade. Kallar, the oldest immigrants Nadar Christians. of Neolithic period with Mediterranean racial elements (Wells et al. 2001) had equitable exchange with Sengundar Mudaliar and Maravar. They had unequal exchange of genes Migrant populations: admixture by Tamil speaking ethnic with Pallan. They had not exchanged with Agamudaiyar, populations Chakkiliyar, Gavara Naidu and Meenavar. Their close rela- North Indian Jain and Gypsy are well-known pan-Indian eth- tionship with branch D ethnic groups is fully justified con- nic groups due to the very nature of their occupation and sidering the exchange of mitochondrial genes with them.

198 Journal of Genetics, Vol. 90, No. 2, August 2011 Genetic structure of Tamil Nadu ethnic groups

Kallar contributed more genes to Maravar than what they genes from the Iyer greater than they contributed to them. could receive from the latter. This suggests that initially Brahmin groups did not exchange the genes with Agamu- Maravar could have evolved from Kallar as a split group daiyar, Chakkiliyar, Gavara Naidu, Meenavar, Nadar Hindu and later admixed with other ethnic groups. This means that and Parayan. Iyengar had equitable exchange of genes with Kallar and Maravar could have shared heredity. Agamudaiyar Agamudaiya Vellalar and Vanniyar. With the remaining pop- formed a close cluster with Chakkiliyar, an early settler of ulations they had unequal exchange of genes. Thus Brahmins the region some 20 to 15 kya (Malhotra et al. 1981). In exchanged with both branch D and C ethnic groups and this admixture analysis, Agamudaiyar exchanged mitochondrial is reflected in NJ tree (figure 1). After their split, they could genes with scheduled castes, Gavara Naidu, Ambalakarar, have independently admixed with other culturally advanced Meenavar and Nadar Hindu. Apart from Kallar and Maravar, ethnic groups. they had not exchanged mitochondrial genes with 11 ethnic groups. Like Chakkiliyar they are an ‘isolated’ ethnic group. Other ethnic groups: Reddiyar and Gavara Naidu are known Although, they are part of Thevar group, genetically they to be a Telugu speaking migrant from Andhra Pradesh dur- showed greater proximity to the Chakkiliyar. ing the period of Vijayanagar empire (16th century; Sanghvi et al. 1981). Traditionally they are agriculturists. In the ear- Religious subdivision lier study on Reddiyar using autosomal markers, Vijaya et al. (2007) found them to cluster along with most ancient Nadars: Traditionally, Nadars are toddy tappers who later ethnic groups. In contrast, in this study they were clustered adopted trade and agriculture as primary occupations. By with the Vellalars. They exchanged more with branch C than 19th century, Christianity influenced them so much so that with subbranch D2 ethnic groups. This implies that they they split into two subgroups: Nadar Hindu and Nadar might have arrived later than the early settlers. Being an Christian (Singh 1997). Overall, Nadar Hindu has exchanged agricultural community, they could have shared mitochon- mitochondrial genes with the culturally less advanced eth- drial genes more with the Vellalar groups. Being landowners, nic groups of branch D than with branch C ethnic groups their clustering with the early settlers in the previous study (figure 1;table4). This could be a reason for its reloca- is not totally unexpected. Surprisingly, Gavara Naidu had no tion from branch C to branch D when in situ and migrant exchange of mitochondrial genes with Reddiyar, rather had populations were excluded (figure 2). Due to the influence unilateral exchange with Agamudaiya Vellalar, Chakkiliyar, of Christianity, the split group, Nadar Christian later could Thuluva Vellalar and Vanniyar and equitable exchange with have admixed with relatively advanced ethnic groups who Nadar Hindu. were also influenced by Christianity. Nadar Hindu contin- Ambalakarar or Mutracha are known to be early set- ued to maintain exchange with early settlers and with Nadar tlers of Tamil region (Malhotra et al. 1981). They have Christians too. received mitochondrial genes from Agamudaiyar, Chakkili- yar, Gavara Naidu, Iyengar, Kallar, Meenavar, Nadar Hindu, Traditional Agriculturists—The Vellalars: Vellalars are subdi- Pallan, Sengundar Mudaliar, Vanniyar, Veerakodi Vellalar vided into four subgroups corresponding to their specific and Parayan almost in equal proportion, but contributed to ancient geographical areas of inhabitance in Tamil Nadu viz., only some of them (table 4). Pandya (Agamudaiya Vellalar), Kongu (Kongu Vellala Meenavar are fisherfolk inhabiting the coastal line of Gounder), Thondaimandalam (Thuluva Vellalar) and Soliya Tamil Nadu. They are known to be highly influenced by (Veerakodi Vellalar; Thurston 1975). These populations Christianity (Singh 1997). In NJ tree they formed subcluster which share a common suffix Vellalar and with similar occu- D1b1.11 with Agamudaiyar and Chakkiliyar (figure 1). With pation are expected to be genetically closer. Agamudaiya autosomal DNA markers also they formed a close cluster Vellalar, Kongu Vellala Gounder and Thuluva Vellalar had with Parayan, an earliest settler of this region (Kanthimathi equitable exchange of genes among themselves. This implies et al. 2008). Meenavar contributed unilaterally to Aga- that with exception of Veerakodi Vellalar other Vellalars did mudaiyar and Chakkiliyar and had bilateral but unequal not have social constrains to exchange genes among them. exchange with Parayan. They had equitable exchange with Veerakodi Vellalar had greater affinity towards branch D Nadar Hindu and contributed to Nadar Christian also. Like populations, whereas other Vellalars did exchange more with Chakkiliyar and Agamudaiyar, they had exchanged genes the branch C ethnic groups (table 4). only with nine ethnic groups. Based on their biological prox- imity with the Parayan, Meenavar could be considered as Brahmins: Brahmins occupy highest social status in the contemporaneous of Parayan and probably isolated by way Hindu caste hierarchy. In Tamil Nadu, Brahmins belong to of their specialized occupation, marine fishing. two major groups: Iyer and Iyengar. The latter are con- Nattukkottai Chettiar, a numerically small trading com- sidered to be a split group of the former who admixed munity (size, 94,260; Second Backward Class Commission with other ethnic groups (Sanghvi and Balakrishnan 1981). 1989), occupy the highest position among nonBrahmins They are supposed to have entered this region about 5 to 3 (Singh 1997). Admixture proportions imply that they had kya (Malhotra et al. 1981). Iyengar received mitochondrial exchanged mitochondrial genes more with the ethnic groups

Journal of Genetics, Vol. 90, No. 2, August 2011 199 G. Suhasini et al. 0000 Hybrid Admixture proportion of 21 ethnic populations of Tamil Nadu based on mtDNA polymorphic markers. Table 4. Parental AVAV AMBAMB ARAR 0.0433CH CHGN 0.0040 0.0854IYN 0.0002 0.0000 GN 0.0605 0.0000IYR 0.0265 0.0863 0.1357 0.0000 0.0887 0.0855 0.0863 IYNKG 0.0003 0.0393 0.2648 0.0854 0.0886 0.0001 0.0024 0.0002KL 0.0000 0.0812 0.0001 IYR 0.2357 0.0000 0.0000 0.0870MR 0.0001 0.1384 0.0000 0.0862 0.0003 0.0660 0.0436 0.0001 0.0000 0.0000 0.0723MV 0.0178 KG 0.0001 0.0000 0.0005 0.0864 0.0000 0.0002 0.0001 0.0675 0.0001 0.0474 0.0854 0.0000NH 0.0000 0.0001 0.0001 0.0822 0.0002 0.0003 0.0003 0.0000 0.0692 0.0000 0.0001 KL 0.0002 0.0001NK 0.0000 0.0864 0.0478 0.0011 0.0230 0.0000 0.0002 0.0402 0.0008 0.0003 0.0855 0.0762 0.0096 0.1006 0.0000 0.0659 0.0001PLN 0.0001 0.1209 0.0864 0.0886 0.0223 0.0003 0.0393 0.0003 0.0927 0.0388 MR 0.0518 0.0002 0.0854 0.0813 0.0000 0.0001RY 0.0833 0.0665 0.0772 0.0752 0.0001 0.0001 0.0003 0.0220 0.0572 0.1189 0.2062 0.0002 0.0850 0.0812 0.0926 0.0002 0.0000 0.0863 0.0072 0.0001 0.2354 0.0001SM 0.0003 0.1179 0.0927 0.1136 0.0002 MV 0.0002 0.0000 0.0854 0.0005 0.0005 0.0002 0.1126 0.0002 0.0002 0.0907 0.0423 0.0001 0.0000 0.0000 0.2603TV 0.0001 0.0001 0.0001 0.0008 0.0863 0.0252 0.0002 0.0002 0.0333 0.0957 0.0002 0.0003 0.2040 0.0000 0.0001 0.0008 0.0005 0.0000 0.0013 0.0001 0.0516 0.1534 NHVAN 0.0001 0.0886 0.2133 0.0862 0.0001 0.0001 0.0002 0.0000 0.0944 0.0383 0.0010 0.1006 0.0001 0.0813 0.0887 0.0854 0.0001 0.0327VLR 0.0000 0.0437 0.0192 0.0927 0.0001 0.0786 0.0000 0.0927 0.0812 0.0863 0.0034 0.1126 0.0001 0.0864 0.0016 0.0001 0.0536 0.0008 0.0606 0.0430 NK 0.0001 0.1608 0.0927 0.0000 0.0005YR 0.1161 0.0854 0.0652 0.0000 0.0066 0.1210 0.0002 0.0850 0.0673 0.0002 0.0927 0.1406 0.0000 0.0244 0.0001 0.0000 0.0812 0.0025 0.0034 0.0003 0.1006 0.1137PA 0.0000 0.0000 0.0927 0.0000 0.0680 PLN 0.0854 0.0000 0.0910 0.0532 0.1102 0.1531 0.0329 0.0707 0.0894 0.0001 0.1695 0.0014 0.0811 0.0000 0.0549 0.0050 0.0285 0.0266 0.1210Total 0.0838 0.0002 0.0002 0.1205 0.0840 0.0001 0.0814 0.0000 0.0886 0.0695 0.0757 0.0000 0.1195 0.0634 0.1008 0.1527 0.0812 0.0000 0.1231 RY 0.0003 0.0650 0.0002 0.0002 0.0948 0.0002 0.0002 0.0009 0.0002 0.0927 0.0000 0.0831 1.0000 0.0886 0.0927 0.0000 0.0000 0.0850 0.0002 0.0917 0.0947 0.0854 0.0568 0.0000 0.2031 1.0000 0.0597 0.0761 0.0802 0.0038 0.0760 0.1137 0.0002 0.0638 0.2647 0.0518 0.0008 0.1199 SM 1.0000 0.0001 0.0926 0.0091 0.0001 0.0085 0.0002 0.1102 0.2356 0.0006 0.0886 0.0357 0.0003 1.0000 0.0809 0.0002 0.0542 0.1785 0.0002 0.0636 0.2740 0.0001 0.0812 0.0897 0.1008 1.0000 0.0454 0.0007 0.0001 0.0001 0.0002 0.0002 0.0638 0.0927 0.0145 0.0040 0.0967 TV 1.0000 0.0002 0.0869 0.0001 0.0003 0.0001 0.0307 0.0201 0.0948 0.0665 1.0000 0.0000 0.1534 0.0001 0.0275 0.0235 0.1008 0.0921 0.0850 0.0948 1.0000 0.0086 0.1008 0.0001 VAN 0.0402 0.0561 0.0002 0.0042 0.0851 1.0000 0.1534 0.0760 0.0000 0.0099 0.0699 0.0000 0.1375 0.1137 1.0000 0.0006 0.0524 0.0733 VLR 0.1937 0.1024 0.0706 0.1375 1.0000 0.0253 0.0639 0.1202 0.0289 0.2061 0.0949 1.0000 0.0233 0.0022 0.1156 0.1008 0.0674 1.0000 0.0851 YR 0.1032 0.1158 0.0296 0.0871 1.0000 0.0044 0.0001 0.0948 0.0850 0.0001 1.0000 0.1775 0.0851 0.0427 0.2198 1.0000 0.1137 PA 0.0244 0.0701 0.1126 1.0000 0.0581 0.0002 0.0002 1.0000 0.0002 0.0856 1.0000 0.0464 0.0003 1.0000 0.0002 1. 0.0013

200 Journal of Genetics, Vol. 90, No. 2, August 2011 Genetic structure of Tamil Nadu ethnic groups

of its existence and some of them became isolated for con- siderable length of time. In spite of the rigidity in the caste system, the built in flexibility allowed maternal gene flow between them.

Acknowledgements

This work was partly supported by a grant from Department of Biotechnology, Govt. of India. We thank Prof. K N Poonuswamy and Prof. M R Srinivasan for their advice in statistical analysis.

References

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Received 15 January 2010, in final revised form 16 October 2010; accepted 7 December 2010 Published on the Web: 19 August 2011

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