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Characterizing the genetic differences between two distinct migrant groups from Indo-European and Dravidian speaking populations in India.

Ali M, Liu X, Pillai EN, Chen P, Khor CC, Ong RT, Teo YY - BMC Genet. (2014)

Bottom Line: We implemented three population genetics measures to identify genomic regions that are significantly differentiated between the two Indian populations originating from the north and south of India.These measures singled out genomic regions with: (i) SNPs exhibiting significant variation in allele frequencies in the two Indian populations; and (ii) differential signals of positive natural selection as quantified by the integrated haplotype score (iHS) and cross-population extended haplotype homozygosity (XP-EHH).Our finding points to a gene-flow from Europe to north India that provides an explanation for the lighter skin tones present in North Indians in comparison to South Indians.

View Article: PubMed Central - HTML - PubMed

Affiliation: Life Sciences Institute, National University of Singapore, Singapore, Singapore. statyy@nus.edu.sg.

ABSTRACT

Background: India is home to many ethnically and linguistically diverse populations. It is hypothesized that history of invasions by people from Persia and Central Asia, who are referred as Aryans in Hindu Holy Scriptures, had a defining role in shaping the Indian population canvas. A shift in spoken languages from Dravidian languages to Indo-European languages around 1500 B.C. is central to the Aryan Invasion Theory. Here we investigate the genetic differences between two sub-populations of India consisting of: (1) The Indo-European language speaking Gujarati Indians with genome-wide data from the International HapMap Project; and (2) the Dravidian language speaking Tamil Indians with genome-wide data from the Singapore Genome Variation Project.

Results: We implemented three population genetics measures to identify genomic regions that are significantly differentiated between the two Indian populations originating from the north and south of India. These measures singled out genomic regions with: (i) SNPs exhibiting significant variation in allele frequencies in the two Indian populations; and (ii) differential signals of positive natural selection as quantified by the integrated haplotype score (iHS) and cross-population extended haplotype homozygosity (XP-EHH). One of the regions that emerged spans the SLC24A5 gene that has been functionally shown to affect skin pigmentation, with a higher degree of genetic sharing between Gujarati Indians and Europeans.

Conclusions: Our finding points to a gene-flow from Europe to north India that provides an explanation for the lighter skin tones present in North Indians in comparison to South Indians.

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Related in: MedlinePlus

Geography and language distribution of India. In this map of India, all the states have been shaded according to the languages predominantly spoken in those states. The two broad language families are: (i) Dravidian (darker shade); and (ii) Indo-Aryan (lighter shade). There is a clear north–south divide, with northern states predominantly speaking Indo-Aryan languages such as Hindi, Marathi, Oriya, Punjabi and Gujarati; while southern states predominantly speak Dravidian languages such as Tamil, Malayalam, Kannada and Telugu. The two groups of samples used in this report trace their ancestries to different ethno-linguistic groups found at different geographical locations. The Houston Gujaratis (GIH) trace their ancestry to the Gujarati-speaking state of Gujarat (red star), while the Singapore Indians (INS) trace their ancestry predominantly to Tamil Nadu, a Dravidian-language speaking state in the south (grey star).
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Figure 1: Geography and language distribution of India. In this map of India, all the states have been shaded according to the languages predominantly spoken in those states. The two broad language families are: (i) Dravidian (darker shade); and (ii) Indo-Aryan (lighter shade). There is a clear north–south divide, with northern states predominantly speaking Indo-Aryan languages such as Hindi, Marathi, Oriya, Punjabi and Gujarati; while southern states predominantly speak Dravidian languages such as Tamil, Malayalam, Kannada and Telugu. The two groups of samples used in this report trace their ancestries to different ethno-linguistic groups found at different geographical locations. The Houston Gujaratis (GIH) trace their ancestry to the Gujarati-speaking state of Gujarat (red star), while the Singapore Indians (INS) trace their ancestry predominantly to Tamil Nadu, a Dravidian-language speaking state in the south (grey star).

Mentions: The presence of the caste system along with two major distinct language families has altered the mating pattern in Indian societies, and this has magnified the diversity of the gene pools that are present in the Indian subcontinent. One of the most apparent differences between north Indians and south Indians is in skin complexion, where north Indians are much fairer compared to the darker south Indians[12]. In this paper, we investigate genome-wide single nucleotide polymorphism (SNP) data from two Indian subpopulations: (i) the Gujaratis from Houston in Phase 3 of the International HapMap Project[13]; and (ii) the south Asian Indians from Singapore in the Singapore Genome Variation Project[14] (Figure 1). The Gujarati samples trace their roots to the Western State of Gujarat where the native language of the ethnic subgroup is classified as Indo-Aryan. The Indian population in Singapore predominantly descended from immigrants from Dravidian-speaking states of Kerala, Karnataka and Tamil Nadu, and thus most Singapore Indians can be regarded as representatives of the broader category of Dravidian-speaking south Indians[15].


Characterizing the genetic differences between two distinct migrant groups from Indo-European and Dravidian speaking populations in India.

Ali M, Liu X, Pillai EN, Chen P, Khor CC, Ong RT, Teo YY - BMC Genet. (2014)

Geography and language distribution of India. In this map of India, all the states have been shaded according to the languages predominantly spoken in those states. The two broad language families are: (i) Dravidian (darker shade); and (ii) Indo-Aryan (lighter shade). There is a clear north–south divide, with northern states predominantly speaking Indo-Aryan languages such as Hindi, Marathi, Oriya, Punjabi and Gujarati; while southern states predominantly speak Dravidian languages such as Tamil, Malayalam, Kannada and Telugu. The two groups of samples used in this report trace their ancestries to different ethno-linguistic groups found at different geographical locations. The Houston Gujaratis (GIH) trace their ancestry to the Gujarati-speaking state of Gujarat (red star), while the Singapore Indians (INS) trace their ancestry predominantly to Tamil Nadu, a Dravidian-language speaking state in the south (grey star).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4120727&req=5

Figure 1: Geography and language distribution of India. In this map of India, all the states have been shaded according to the languages predominantly spoken in those states. The two broad language families are: (i) Dravidian (darker shade); and (ii) Indo-Aryan (lighter shade). There is a clear north–south divide, with northern states predominantly speaking Indo-Aryan languages such as Hindi, Marathi, Oriya, Punjabi and Gujarati; while southern states predominantly speak Dravidian languages such as Tamil, Malayalam, Kannada and Telugu. The two groups of samples used in this report trace their ancestries to different ethno-linguistic groups found at different geographical locations. The Houston Gujaratis (GIH) trace their ancestry to the Gujarati-speaking state of Gujarat (red star), while the Singapore Indians (INS) trace their ancestry predominantly to Tamil Nadu, a Dravidian-language speaking state in the south (grey star).
Mentions: The presence of the caste system along with two major distinct language families has altered the mating pattern in Indian societies, and this has magnified the diversity of the gene pools that are present in the Indian subcontinent. One of the most apparent differences between north Indians and south Indians is in skin complexion, where north Indians are much fairer compared to the darker south Indians[12]. In this paper, we investigate genome-wide single nucleotide polymorphism (SNP) data from two Indian subpopulations: (i) the Gujaratis from Houston in Phase 3 of the International HapMap Project[13]; and (ii) the south Asian Indians from Singapore in the Singapore Genome Variation Project[14] (Figure 1). The Gujarati samples trace their roots to the Western State of Gujarat where the native language of the ethnic subgroup is classified as Indo-Aryan. The Indian population in Singapore predominantly descended from immigrants from Dravidian-speaking states of Kerala, Karnataka and Tamil Nadu, and thus most Singapore Indians can be regarded as representatives of the broader category of Dravidian-speaking south Indians[15].

Bottom Line: We implemented three population genetics measures to identify genomic regions that are significantly differentiated between the two Indian populations originating from the north and south of India.These measures singled out genomic regions with: (i) SNPs exhibiting significant variation in allele frequencies in the two Indian populations; and (ii) differential signals of positive natural selection as quantified by the integrated haplotype score (iHS) and cross-population extended haplotype homozygosity (XP-EHH).Our finding points to a gene-flow from Europe to north India that provides an explanation for the lighter skin tones present in North Indians in comparison to South Indians.

View Article: PubMed Central - HTML - PubMed

Affiliation: Life Sciences Institute, National University of Singapore, Singapore, Singapore. statyy@nus.edu.sg.

ABSTRACT

Background: India is home to many ethnically and linguistically diverse populations. It is hypothesized that history of invasions by people from Persia and Central Asia, who are referred as Aryans in Hindu Holy Scriptures, had a defining role in shaping the Indian population canvas. A shift in spoken languages from Dravidian languages to Indo-European languages around 1500 B.C. is central to the Aryan Invasion Theory. Here we investigate the genetic differences between two sub-populations of India consisting of: (1) The Indo-European language speaking Gujarati Indians with genome-wide data from the International HapMap Project; and (2) the Dravidian language speaking Tamil Indians with genome-wide data from the Singapore Genome Variation Project.

Results: We implemented three population genetics measures to identify genomic regions that are significantly differentiated between the two Indian populations originating from the north and south of India. These measures singled out genomic regions with: (i) SNPs exhibiting significant variation in allele frequencies in the two Indian populations; and (ii) differential signals of positive natural selection as quantified by the integrated haplotype score (iHS) and cross-population extended haplotype homozygosity (XP-EHH). One of the regions that emerged spans the SLC24A5 gene that has been functionally shown to affect skin pigmentation, with a higher degree of genetic sharing between Gujarati Indians and Europeans.

Conclusions: Our finding points to a gene-flow from Europe to north India that provides an explanation for the lighter skin tones present in North Indians in comparison to South Indians.

Show MeSH
Related in: MedlinePlus