Genetic studies on Sinhalese

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.

Some of the older studies looking at the origin of the Sinhalese erroneously 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]

A 2017 study conducted by Fumihiko Takeuchi, Tomohiro Katsuya, Ryosuke Kimura and Norihiro Kato showed that the main ancestral population that contributed to the Sinhalese was the "South Asian" component with a significant contribution from the "South Asian and Central Asian" component and smaller contributions from the "Central Asian", "Southeast Asian", "Southeast Asian and East Asian", "East Asian" and "Japanese" components.[6]

Relationship to Bengalis

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.[7] The Sinhalese also have similar frequencies of the allele MTHFR 677T (13%) to West Bengalis (17%).[8][9]

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.[10] 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.

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]

Relationship to other ethnic groups in Sri Lanka

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.[12] 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][13][14] Another study has also found "no significant genetic variation among the major ethnic groups in Sri Lanka".[15] 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.[9]

Relationship to East and Southeast Asians

Genetic studies show that the Sinhalese have received some genetic flow from neighboring populations in East Asia and Southeast Asia, such as from the ethnically diverse and disparate Tibeto-Burman peoples and Austro-Asiatic peoples,[16] 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][21] In regards to comparisons of root and canal morphology of Sri Lankan mandibular molars, it showed that they were further away from Mongoloid populations.[22] 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.[23] In regards to Y-DNA, Haplogroup C-M130 is found at low to moderate frequencies in Sri Lanka.[24]

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.[25] 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.[25] At a lower frequency, ab3st is also found among the Sinhalese and is generally found at higher frequencies among northern Han Chinese, Tibetan, Mongolian, Korean and Japanese populations.[25] The Transferrin TF*Dchi allele which is common among East Asian and Native American populations is also found among the Sinhalese.[20] HumDN1*4 and HumDN1*5 are the predominant DNase I genes among the Sinhalese and are also the predominant genes among southern Chinese ethnic groups and the Tamang people of Nepal.[26] A 1988 study conducted by N. Saha, showed the high GC*1F and low GC*1S frequencies among the Sinhalese are comparable to those of the Chinese, Japanese, Koreans, Thais, Malays, Vietnamese, Laotians and Tibetans.[27] A 1998 study conducted by D.E. Hawkey showed dental morphology of the Sinhalese is closely related to those of the Austro-Asiatic populations of East and Northeast India.[16] Hemoglobin E a variant of normal hemoglobin, which originated in and is prevalent among populations in Southeast Asia, is also common among the Sinhalese and can reach up to 40% in Sri Lanka.[28]

Skin pigmentation

In 2008 a study looked at SLC24A5 polymorphism which accounts for 25-40% of the skin complexion difference between Europeans and Africans and up to 30% of skin colour variation in South Asians.[29] The study found that the rs1426654 SNP of SLC24A5, which is fixed in European populations[30] 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.[29] 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

  1. ↑ Kshatriya GK (December 1995). "Genetic affinities of Sri Lankan populations". Human Biology. 67 (6): 843–66. PMID 8543296.
  2. 1 2 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. 1 2 3 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. 1 2 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. 1 2 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. ↑ https://www.researchgate.net/publication/320787828_The_fine-scale_genetic_structure_and_evolution_of_the_Japanese_population
  7. ↑ Surinder Singh Papiha (1999). Genomic Diversity: Applications in Human Population Genetics. London: Springer. 7.
  8. ↑ Mukhopadhyay, 2007 K. Mukhopadhyay et al., MTHFR gene polymorphisms analyzed in population from Kolkata, West Bengal, Indian J. Human Genet. 13 (2007), p. 38.
  9. 1 2 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
  10. 1 2 Kivisild, Toomas; et al. (2003). "The Genetics of Language and Farming Spread in India". In Bellwood P, Renfrew C. Examining the farming/language dispersal hypothesis (PDF). Cambridge, United Kingdom: McDonald Institute for Archaeological Research. pp. 215–222.
  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. ↑ 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.
  13. ↑ 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: https://www.jstor.org/stable/2799860
  14. ↑ 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.
  15. ↑ 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
  16. 1 2 Hawkey, D E (1998). "Out of Asia: Dental evidence for affinity and microevolution of early and recent populations of India and Sri Lanka".
  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 379225. 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 1380230. PMID 16400607.
  20. 1 2 Roychoudhury AK; Nei M (1985). "Genetic relationships between Indians and their neighboring populations" (PDF). Hum Hered. 35: 201–6. doi:10.1159/000153545. PMID 4029959.
  21. ↑ M. K. Bhasin (2009). "Morphology to Molecular Anthropology: Castes and Tribes of India" (PDF). Int J Hum Genet.
  22. ↑ 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.
  23. ↑ http://www.nature.com/jhg/journal/v59/n1/full/jhg2013112a.html
  24. ↑ "Y-DNA Haplogroup C and its Subclades - 2017". International Society of Genetic Genealogy. Retrieved 31 May 2017.
  25. 1 2 3 Hideo Matsumoto (2009). "The origin of the Japanese race based on genetic markers of immunoglobulin G". Proc Jpn Acad Ser B Phys Biol Sci. 85 (2): 69–82. doi:10.2183/pjab.85.69. PMC 3524296. PMID 19212099.
  26. ↑ Fujihara, J; Yasuda, T; Iida, R; Ueki, M; Sano, R; Kominato, Y; Inoue, K; Kimura-Kataoka, K; Takeshita, H. "Global analysis of genetic variations in a 56-bp variable number of tandem repeat polymorphisms within the human deoxyribonuclease I gene". Leg Med (Tokyo). 17: 283–6. doi:10.1016/j.legalmed.2015.01.005. PMID 25771153.
  27. ↑ https://books.google.com/books?id=U6WhkmvI324C&printsec=frontcover#v=onepage&q&f=false
  28. ↑ https://books.google.com/books?id=2grSBwAAQBAJ&printsec=frontcover#v=onepage&q&f=false
  29. 1 2 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.
  30. ↑ 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.
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