Genetic studies on Sinhalese

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The hypothesized migration routes of the ancestors of the Sinhalese and other ethnic groups into Sri Lanka.

Genetic studies on the Sinhalese is part of population genetics investigating the origins of the Sinhalese populations today.

Studies looking at the origin of the Sinhalese have been contradictory. Older studies suggest a predominantly Tamil origin followed by a significant Bengali contribution with a slight North Western Indian contribution.[1][2] While modern studies using more sophisticated testing point towards a predominantly Bengali contribution and a minor South Indian Tamil and North Western Indian contribution respectively.[3][4][5]

All studies agree however, that there is a significant relationship between the Sinhalese and the South Indian Tamils and Bengalis and that there is a significant genetic relationship between Sri Lankan Tamils and Sinhalese, them being closer to each other than other South Asian populations. This is also supported by a genetic distance study, which showed low differences in genetic distance between the Sinhalese and the Tamil, Keralite and Bengali volunteers.[3]

Predominantly Bengali origin[edit]

Genetic26526 admixture of Sinhalese by Dr. Saha Papiha

An Alu polymorphism analysis of Sinhalese from Colombo by Dr Sarabjit Mastanain in 2007 using Tamil, Bengali, Gujarati (Patel), and Punjabi as parental populations found different proportions of genetic contribution:[5]

Statistical Method Bengali Tamil North Western
Point Estimate 57.49% 42.5% -
Maximum Likelihood Method 88.07% - -
Using Tamil, Bengali and North West as parenteral population 50-66% 11-30% 20-23%

A genetic distance analysis by Dr Robet Kirk also concluded that the modern Sinhalese are most closely related to the Bengalis.[3]

This is further substantiated by a VNTR study, which found 70-82% of Sinhalese genes to originate from Bengali admixture:[4]

Parenteral population Bengali Tamil Gujarati Punjabi
Using Tamil and Bengali as parenteral population 70.03% 29.97% -
Using Tamil, Bengali and Gujarati as parenteral population 71.82% 16.38% 11.82%
Using Bengal, Gujarati and Punjabi as parenteral population 82.09% - 15.39% 2.52%

D1S80 allele frequency (A popular allele for genetic fingerprinting) is also similar between the Sinhalese and Bengalis, suggesting the two groups are closely related.[6] The Sinhalese also have similar frequencies of the allele MTHFR 677T (13%) to West Bengalis (17%).[7][8]

A test for Y-chromosome DNA haplogroups conducted by Dr Toomas Kivisild on Sinhalese of Sri Lanka has shown that 23% of the subjects were R1a1a (R-SRY1532) positive.[9] Also in the same test 24.1% of the subjects were R2 positive as subclades of Haplogroup P (92R7).[10] Haplogroup R2 is also found in a considerable percentage among Bengalis of India. Sample size used was 87 subjects.

These findings are compatible with the historical chronicles the Mahavamsa and Dipavamsa. Which describe a Vanga prince (Prince Vijaya)from Sinhapura in Lata or Lala of being an early settler of Sri Lanka and the progenitor of the Sinhalese. The Vangas are generally identified as Bengalis. On the other hand, Lata is identified with modern-day Gujarat, and Sinhapura with modern Sihor in the Kathiawar peninsular of Gujarat. Furthermore, the Mahawamsa states that Vijaya landed first at Supparaka (identified with modern Sopara, in the Thane district of Maharashtra), while the Dipavamsa mentions 'Suppara' and a further intermediate port, Bharukkaccha (modern Bharuch, a port in Gujarat, at the mouth of the Narmada). Vijaya's grandfather was reputed to be a lion, and lions have not lived in Bengal in historic times, while they have in Gujarat so it was possible that the lion image was borrowed from there.

Genetic distance of Sinhalese to other ethnic groups in the Indian Subcontinent according to an Alu Polymorphism analysis.
Genetic distance of Sinhalese to other ethnic groups.

A study in 2007 found similar frequencies of the allele HLA-A*02 in sinhalese (7.4%) and North Indian subjects (6.7%). HLA-A*02 is a rare allele which has a relatively high frequency in North Indian populations and is considered to be a novel allele among the North Indian population. This suggests possible North Indian origin of the Sinhalese.[11]

Linguistically the Sinhalese are closer to North Indians than South Indians, as the Sinhala language is a member of the Indo-Aryan languages.[12] On the other hand, South Indians speak languages belonging to the Dravidian languages. The Sinhalese therefore can trace a connection to their North Indian origins through this. Not only this but the Sinhalese predominantly follow Theravada Buddhism and for centuries maintained strong connections with North Eastern India, while it too was predominantly Buddhist. This further strengthens the connection of migration between the two well after the believed initial North Indian migration to Sri Lanka.

Relationship to other ethnic groups in Sri Lanka[edit]

A study looking at genetic variation of the FUT2 gene in the Sinhalese and Sri Lankan Tamil population, found similar genetic backgrounds for both ethnic groups, with little genetic flow from other neighbouring Asian population groups.[13] Studies have also found no significant difference with regards to blood group, blood genetic markers and single-nucleotide polymorphism between the Sinhalese and other ethnic groups in Sri Lanka.[2][14][15] Another study has also found "no significant genetic variation among the major ethnic groups in Sri Lanka".[16] This is further supported by a study which found very similar frequencies of alleles MTHFR 677T, F2 20210A & F5 1691A in South Indian Tamil, Sinhalese, Sri Lankan Tamil and Moor populations.[8]

Relationship to East Asians[edit]

Genetic studies show that the Sinhalese have received some genetic flow from neighboring populations in East Asia, such as from the ethnically diverse and disparate peoples of Sino-Tibetan linguistic origins, which is due to their close genetic links to Northeast India.[17][18][19] A 1985 study conducted by Roychoudhury AK and Nei M, indicated the values of genetic distance showed that the Sinhalese people were slightly closer to Mongoloid populations due to gene exchange in the past.[20] In regards to comparisons of root and canal morphology of Sri Lankan mandibular molars, it showed that they were further away from Mongoloid populations.[21] Among haplogroups found in East Asian populations, a lower frequency of East Asian mtDNA haplogroup, G has been found among the populations of Sri Lanka alongside haplogroup D in conjunction with the main mtDNA haplogroup of Sri Lanka's ethnic groups, haplogroup M.[22] In regards to Y-DNA, Haplogroup C-M130 is found at low to moderate frequencies in Sri Lanka.[23]

Genetic markers of immunoglobulin among the Sinhalese show high frequencies of afb1b3 which has its origins in the Yunnan and Guangxi provinces of southern China and is an East Asian gene. It is also found at high frequencies among Bengalis, certain Nepali and northeast Indian, southern Han Chinese, Southeast Asian and certain Austronesian populations of the Pacific Islands. At a lower frequency, ab3st is found among the Sinhalese and is generally found at higher frequencies among northern Han Chinese, Tibetan, Mongolian, Korean and Japanese populations.[24]

Skin pigmentation[edit]

In 2008 a study looked at SLC24A5 polymorphism which accounts for 25-40% of the skin complexion difference between Europeans and Africans[25] and up to 30% of skin colour variation in South Asians.[26][27] The study found that the rs1426654 SNP of SLC24A5, which is fixed in European populations[28] and found more commonly in light skinned individuals than dark skinned individuals (49% compared to 10%), has a frequency of 50-55% in the Sinhalese and 25-30% in Sri Lankan Tamils.[27] This allele could have arisen in the Sinhalese due to strong East Asian genetic admixture, further migration from North India or strong selection factors.

References[edit]

  1. ^ Kshatriya GK (December 1995). "Genetic affinities of Sri Lankan populations". Human Biology. 67 (6): 843–66. PMID 8543296. 
  2. ^ a b Saha, N. (1988). "Blood genetic markers in Sri Lankan populations—reappraisal of the legend of Prince Vijaya". American Journal of Physical Anthropology. 76 (2): 217–25. doi:10.1002/ajpa.1330760210. PMID 3166342. 
  3. ^ a b c Kirk, R. L. (1976). "The legend of Prince Vijaya — a study of Sinhalese origins". American Journal of Physical Anthropology. 45 (1): 91–99. doi:10.1002/ajpa.1330450112. 
  4. ^ a b Papiha SS, Mastana SS, Purandare CA, Jayasekara R, Chakraborty R (October 1996). "Population genetic study of three VNTR loci (D2S44, D7S22, and D12S11) in five ethnically defined populations of the Indian subcontinent". Human Biology. 68 (5): 819–35. PMID 8908803. 
  5. ^ a b http://www.krepublishers.com/06-Special%20Volume-Journal/T-Anth-00-Special%20Volumes/T-Anth-SI-03-Anth-Today-Web/Anth-SI-03-29-Mastana-S/Anth-SI-03-29-Mastana-S-Tt.pdf
  6. ^ Surinder Singh Papiha (1999). Genomic Diversity: Applications in Human Population Genetics. London: Springer. 7.
  7. ^ Mukhopadhyay, 2007 K. Mukhopadhyay et al., MTHFR gene polymorphisms analyzed in population from Kolkata, West Bengal, Indian J. Human Genet. 13 (2007), p. 38.
  8. ^ a b Vajira H.W. Dissanayake, Lakshini Y. Weerasekera, C. Gayani Gammulla, Rohan W. Jayasekara, Prevalence of genetic thrombophilic polymorphisms in the Sri Lankan population -- implications for association study design and clinical genetic testing services, Experimental and Molecular Pathology, Volume 87, Issue 2, October 2009, Pages 159-162
  9. ^ "Kivisild, Toomas; et al. (2003a). "The Genetics of Language and Farming Spread in India". In Bellwood P, Renfrew C. Examining the farming/language dispersal hypothesis (PDF). McDonald Institute for Archaeological Research, Cambridge, United Kingdom. pp. 215–222." (PDF). 
  10. ^ "Kivisild, Toomas; et al. (2003a). "The Genetics of Language and Farming Spread in India". In Bellwood P, Renfrew C. Examining the farming/language dispersal hypothesis (PDF). McDonald Institute for Archaeological Research, Cambridge, United Kingdom. pp. 215–222." (PDF). 
  11. ^ Malavige, G. N.; Rostron, T.; Seneviratne, S. L.; Fernando, S.; Sivayogan, S.; Wijewickrama, A.; Ogg, G. S. (2007). "HLA analysis of Sri Lankan Sinhalese predicts North Indian origin". International Journal of Immunogenetics. 34 (5): 313–5. doi:10.1111/j.1744-313X.2007.00698.x. PMID 17845299. 
  12. ^ Indo-Aryan languages
  13. ^ Soejima M, Koda Y (December 2005). "Denaturing high-performance liquid chromatography-based genotyping and genetic variation of FUT2 in Sri Lanka". Transfusion. 45 (12): 1934–9. doi:10.1111/j.1537-2995.2005.00651.x. PMID 16371047. 
  14. ^ D. F. Roberts, C. K. Creen, K. P. Abeyaratne, Man, New Series, Vol. 7, No. 1 (Mar., 1972), pp. 122-127, Published by: Royal Anthropological Institute of Great Britain and Ireland, Stable URL: http://www.jstor.org/stable/2799860
  15. ^ Dissanayake VH, Giles V, Jayasekara RW, et al. (April 2009). "A study of three candidate genes for pre-eclampsia in a Sinhalese population from Sri Lanka". The Journal of Obstetrics and Gynaecology Research. 35 (2): 234–42. doi:10.1111/j.1447-0756.2008.00926.x. PMID 19708171. 
  16. ^ Ruwan J. Illeperuma, Samudi N. Mohotti, Thilini M. De Silva, Neil D. Fernandopulle, W.D. Ratnasooriya, Genetic profile of 11 autosomal STR loci among the four major ethnic groups in Sri Lanka, Forensic Science International: Genetics, Volume 3, Issue 3, June 2009, Pages e105-e106
  17. ^ Soejima, Mikiko; Koda, Yoshiro (2006). "Population differences of two coding SNPs in pigmentation-related genes SLC24A5 and SLC45A2". International Journal of Legal Medicine. 121 (1): 36–9. doi:10.1007/s00414-006-0112-z. PMID 16847698. 
  18. ^ Kivisild T, Rootsi S, Metspalu M, Mastana S, Kaldma K, Parik J, Metspalu E, Adojaan M, Tolk HV, Stepanov V, Gölge M, Usanga E, Papiha SS, Cinnioğlu C, King R, Cavalli-Sforza L, Underhill PA, Villems R (2003). "The genetic heritage of the earliest settlers persists both in Indian tribal and caste populations". American Journal of Human Genetics. 72 (2): 313–32. doi:10.1086/346068. PMC 379225Freely accessible. PMID 12536373. 
  19. ^ Sengupta S, Zhivotovsky LA, King R, Mehdi SQ, Edmonds CA, Chow CE, Lin AA, Mitra M, Sil SK, Ramesh A, Usha Rani MV, Thakur CM, Cavalli-Sforza LL, Majumder PP, Underhill PA (2006). "Polarity and temporality of high-resolution y-chromosome distributions in India identify both indigenous and exogenous expansions and reveal minor genetic influence of Central Asian pastoralists". American Journal of Human Genetics. 78 (2): 202–21. doi:10.1086/499411. PMC 1380230Freely accessible. PMID 16400607. 
  20. ^ http://www.krepublishers.com/02-Journals/IJHG/IJHG-09-0-000-09-Web/IJHG-09-3-4-000-09-Abst-PDF/IJHG-09-3-4-145-09-Bhasin-M-K/IJHG-09-3-4-145-09-Bhasin-M-K-Tt.pdf
  21. ^ Peiris, Roshan; Takahashi, Masami; Sasaki, Kayoko; Kanazawa, Eisaku (2007). "Root and canal morphology of permanent mandibular molars in a Sri Lankan population". Odontology. 95 (1): 16–23. doi:10.1007/s10266-007-0074-8. PMID 17660977. 
  22. ^ http://www.nature.com/jhg/journal/v59/n1/full/jhg2013112a.html
  23. ^ http://isogg.org/tree/ISOGG_HapgrpC.html
  24. ^ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3524296/
  25. ^ Razib. (2005). Race is skin deep. Available: http://www.gnxp.com/blog/2005/12/race-is-skin-deep.php. Last accessed 3 March 2010.
  26. ^ Razib. (2007). Why brown people are different. Available: . http://scienceblogs.com/gnxp/2007/09/why_brown_people_are_different.php. Last accessed 3 March 2010.
  27. ^ a b Soejima M, Koda Y (January 2007). "Population differences of two coding SNPs in pigmentation-related genes SLC24A5 and SLC45A2". International Journal of Legal Medicine. 121 (1): 36–9. doi:10.1007/s00414-006-0112-z. PMID 16847698. 
  28. ^ Stanford University. (2009). rs1426654 Chromosome chr15:46213776. Available: http://hgdp.uchicago.edu/cgi-bin/alfreqs.cgi?pos=46213776&chr=chr15&rs=rs1426654&imp=true. Last accessed 3 March 2010.

External links[edit]