Genetic studies on the Sinhalese is part of population genetics investigating the origins of the Sinhalese population.
All studies agree that there is a significant relationship between the Sinhalese and the Bengalis and Tamils, 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 Bengali, Tamil, and Keralite volunteers.
According to a study published in 2021 using 16 X-chromosomal short tandem repeat markers (STRs), there was no genetic subdivision detected between Sinhalese, Moors and Sri Lankan Tamils while Indian Tamils were having a subtle but statistically significant difference. The observed close relationship between Moors and Sinhalese maybe explained by the matrimonial bonds made by Moor males with Sinhalese females during their original settlement in Sri Lanka. Further, the phylogram generated for the four main ethnic groups of Sri Lanka was suggestive of an Indian origin for Moors compared to the Arabic origin speculated by some.
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:
|Statistical Method||Bengali||Tamil||North Western|
|Maximum Likelihood Method||88.07%||-||-|
|Using Tamil, Bengali and North West as parental population||50-66%||11-30%||20-23%|
|Using Tamil and Bengali as parental population||70.03%||29.97%||-|
|Using Tamil, Bengali and Gujarati as parental population||71.82%||16.38%||11.82%|
|Using Bengali, Gujarati and Punjabi as parental 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. The Sinhalese also have similar frequencies of the allele MTHFR 677T (13%) to West Bengalis (17%).
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. Also in the same test 24.1% of the subjects were R2 positive as subclades of Haplogroup P (92R7). Haplogroup R2 is also found in a considerable percentage among Bengali of India. Sample size used was 87 subjects.
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.
Main article: Genetic studies on Sri Lankan Tamils
Another study by GK Kshatriya conducted in 1995 assessing the 'Genetic affinities of Sri Lankan Populations' found a large genetic contribution from the Tamils of South India, as well as from the Bengali and Vedda populations.
|Using Tamil, Bengali and Vedda as parental population||69.86%||25.41%||4.73%|
Dr. Sarabjit Mastanain finding states cophenetic correlation was 0.8956 and it indicates Sinhalese & Tamil as native population. Also, it reflects on genetic distance among five populations of Sri Lanka as per given below eigenvector plot of the R-matrix.
|(5 populations of 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. 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. Another study has also found "no significant genetic variation among the major ethnic groups in Sri Lanka". This is further supported by a study which found very similar frequencies of alleles MTHFR 677T, F2 20210A & F5 1691A in Indian Tamil, Sinhalese, Sri Lankan Tamil, and Sri Lankan Moor populations.
A genetic study carried out in 2015 by Lian dang et. on origin of Malay people and other populations of Sri Lanka involving 200 Sinhalese people, 103 Tamil people of Sri Lankan origin, 200 Tamil people of Indian origin and 35 Burgher people calculated the averaged genetic makeup across individuals of each population, which show substantially higher amount of Central Asian ancestry and low South Asian ancestry among Sinhalese compared to both Tamil groups.
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, which is due to their close genetic links to Northeast India. 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. In regards to comparisons of root and canal morphology of Sri Lankan mandibular molars, it showed that they were further away from Mongoloid populations. 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. In regards to Y-DNA, Haplogroup C-M130 is found at low to moderate frequencies in Sri Lanka.
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. It is also found at high frequencies among Odias, certain Nepali and Northeast Indian, southern Han Chinese, Southeast Asian and certain Austronesian populations of the Pacific Islands. 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. The Transferrin TF*Dchi allele which is common among East Asian and Native American populations is also found among the Sinhalese. 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. 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. 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. 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.
A 2021 study focusing on 16 studied X-STR loci, compared four Sri Lankan ethnicities (Sinhalese, Sri Lankan Tamils, Indian Tamils, Moors) with 14 other world populations (Bhil India, Bangladesh, Malaysia, Thailand, China, Japan, Taiwan, Germany, Italy, Sweden, Denmark, North Portugal, Somalia, and Ivory Coast) with eight X chromosome based STR markers using a multidimensional scaling plot (MDS plot), it revealed that Sri Lankans were clustered together not only with South Asians like Indians and Bangladeshis, but also with Europeans. However, allelic distribution of many X-STR loci in Sri Lankan ethnic groups differ from European, Southeast Asian, East Asian and African populations and are most similar to the two Indian populations and Bangladeshi population included in the study.