Mitochondrial and Y-chromosome diversity of the Tharus (Nepal)

A reservoir of genetic variation

Simona Fornarino, Maria Pala, Vincenza Battaglia, Ramona Maranta, Alessandro Achilli, Guido Modiano, Antonio Torroni, Ornella Semino, Silvana A. Santachiara-Benerecetti

Research output: Contribution to journalArticle

50 Citations (Scopus)

Abstract

Background. Central Asia and the Indian subcontinent represent an area considered as a source and a reservoir for human genetic diversity, with many markers taking root here, most of which are the ancestral state of eastern and western haplogroups, while others are local. Between these two regions, Terai (Nepal) is a pivotal passageway allowing, in different times, multiple population interactions, although because of its highly malarial environment, it was scarcely inhabited until a few decades ago, when malaria was eradicated. One of the oldest and the largest indigenous people of Terai is represented by the malaria resistant Tharus, whose gene pool could still retain traces of ancient complex interactions. Until now, however, investigations on their genetic structure have been scarce mainly identifying East Asian signatures. Results. High-resolution analyses of mitochondrial-DNA (including 34 complete sequences) and Y-chromosome (67 SNPs and 12 STRs) variations carried out in 173 Tharus (two groups from Central and one from Eastern Terai), and 104 Indians (Hindus from Terai and New Delhi and tribals from Andhra Pradesh) allowed the identification of three principal components: East Asian, West Eurasian and Indian, the last including both local and inter-regional sub-components, at least for the Y chromosome. Conclusion. Although remarkable quantitative and qualitative differences appear among the various population groups and also between sexes within the same group, many mitochondrial-DNA and Y-chromosome lineages are shared or derived from ancient Indian haplogroups, thus revealing a deep shared ancestry between Tharus and Indians. Interestingly, the local Y-chromosome Indian component observed in the Andhra-Pradesh tribals is present in all Tharu groups, whereas the inter-regional component strongly prevails in the two Hindu samples and other Nepalese populations. The complete sequencing of mtDNAs from unresolved haplogroups also provided informative markers that greatly improved the mtDNA phylogeny and allowed the identification of ancient relationships between Tharus and Malaysia, the Andaman Islands and Japan as well as between India and North and East Africa. Overall, this study gives a paradigmatic example of the importance of genetic isolates in revealing variants not easily detectable in the general population.

Original languageEnglish
Article number154
JournalBMC Evolutionary Biology
Volume9
Issue number1
Early online date2 Jul 2009
DOIs
Publication statusPublished - 11 Aug 2009
Externally publishedYes

Fingerprint

Y chromosome
Nepal
genetic variation
chromosome
India
mitochondrial DNA
malaria
Andaman and Nicobar Islands
indigenous peoples
Central Asia
Northern Africa
Eastern Africa
ancestry
Malaysia
genetic structure
phylogeny
Japan
gene
gender
sampling

Cite this

Fornarino, S., Pala, M., Battaglia, V., Maranta, R., Achilli, A., Modiano, G., ... Santachiara-Benerecetti, S. A. (2009). Mitochondrial and Y-chromosome diversity of the Tharus (Nepal): A reservoir of genetic variation. BMC Evolutionary Biology, 9(1), [154]. https://doi.org/10.1186/1471-2148-9-154
Fornarino, Simona ; Pala, Maria ; Battaglia, Vincenza ; Maranta, Ramona ; Achilli, Alessandro ; Modiano, Guido ; Torroni, Antonio ; Semino, Ornella ; Santachiara-Benerecetti, Silvana A. / Mitochondrial and Y-chromosome diversity of the Tharus (Nepal) : A reservoir of genetic variation. In: BMC Evolutionary Biology. 2009 ; Vol. 9, No. 1.
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Fornarino, S, Pala, M, Battaglia, V, Maranta, R, Achilli, A, Modiano, G, Torroni, A, Semino, O & Santachiara-Benerecetti, SA 2009, 'Mitochondrial and Y-chromosome diversity of the Tharus (Nepal): A reservoir of genetic variation', BMC Evolutionary Biology, vol. 9, no. 1, 154. https://doi.org/10.1186/1471-2148-9-154

Mitochondrial and Y-chromosome diversity of the Tharus (Nepal) : A reservoir of genetic variation. / Fornarino, Simona; Pala, Maria; Battaglia, Vincenza; Maranta, Ramona; Achilli, Alessandro; Modiano, Guido; Torroni, Antonio; Semino, Ornella; Santachiara-Benerecetti, Silvana A.

In: BMC Evolutionary Biology, Vol. 9, No. 1, 154, 11.08.2009.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Mitochondrial and Y-chromosome diversity of the Tharus (Nepal)

T2 - A reservoir of genetic variation

AU - Fornarino, Simona

AU - Pala, Maria

AU - Battaglia, Vincenza

AU - Maranta, Ramona

AU - Achilli, Alessandro

AU - Modiano, Guido

AU - Torroni, Antonio

AU - Semino, Ornella

AU - Santachiara-Benerecetti, Silvana A.

PY - 2009/8/11

Y1 - 2009/8/11

N2 - Background. Central Asia and the Indian subcontinent represent an area considered as a source and a reservoir for human genetic diversity, with many markers taking root here, most of which are the ancestral state of eastern and western haplogroups, while others are local. Between these two regions, Terai (Nepal) is a pivotal passageway allowing, in different times, multiple population interactions, although because of its highly malarial environment, it was scarcely inhabited until a few decades ago, when malaria was eradicated. One of the oldest and the largest indigenous people of Terai is represented by the malaria resistant Tharus, whose gene pool could still retain traces of ancient complex interactions. Until now, however, investigations on their genetic structure have been scarce mainly identifying East Asian signatures. Results. High-resolution analyses of mitochondrial-DNA (including 34 complete sequences) and Y-chromosome (67 SNPs and 12 STRs) variations carried out in 173 Tharus (two groups from Central and one from Eastern Terai), and 104 Indians (Hindus from Terai and New Delhi and tribals from Andhra Pradesh) allowed the identification of three principal components: East Asian, West Eurasian and Indian, the last including both local and inter-regional sub-components, at least for the Y chromosome. Conclusion. Although remarkable quantitative and qualitative differences appear among the various population groups and also between sexes within the same group, many mitochondrial-DNA and Y-chromosome lineages are shared or derived from ancient Indian haplogroups, thus revealing a deep shared ancestry between Tharus and Indians. Interestingly, the local Y-chromosome Indian component observed in the Andhra-Pradesh tribals is present in all Tharu groups, whereas the inter-regional component strongly prevails in the two Hindu samples and other Nepalese populations. The complete sequencing of mtDNAs from unresolved haplogroups also provided informative markers that greatly improved the mtDNA phylogeny and allowed the identification of ancient relationships between Tharus and Malaysia, the Andaman Islands and Japan as well as between India and North and East Africa. Overall, this study gives a paradigmatic example of the importance of genetic isolates in revealing variants not easily detectable in the general population.

AB - Background. Central Asia and the Indian subcontinent represent an area considered as a source and a reservoir for human genetic diversity, with many markers taking root here, most of which are the ancestral state of eastern and western haplogroups, while others are local. Between these two regions, Terai (Nepal) is a pivotal passageway allowing, in different times, multiple population interactions, although because of its highly malarial environment, it was scarcely inhabited until a few decades ago, when malaria was eradicated. One of the oldest and the largest indigenous people of Terai is represented by the malaria resistant Tharus, whose gene pool could still retain traces of ancient complex interactions. Until now, however, investigations on their genetic structure have been scarce mainly identifying East Asian signatures. Results. High-resolution analyses of mitochondrial-DNA (including 34 complete sequences) and Y-chromosome (67 SNPs and 12 STRs) variations carried out in 173 Tharus (two groups from Central and one from Eastern Terai), and 104 Indians (Hindus from Terai and New Delhi and tribals from Andhra Pradesh) allowed the identification of three principal components: East Asian, West Eurasian and Indian, the last including both local and inter-regional sub-components, at least for the Y chromosome. Conclusion. Although remarkable quantitative and qualitative differences appear among the various population groups and also between sexes within the same group, many mitochondrial-DNA and Y-chromosome lineages are shared or derived from ancient Indian haplogroups, thus revealing a deep shared ancestry between Tharus and Indians. Interestingly, the local Y-chromosome Indian component observed in the Andhra-Pradesh tribals is present in all Tharu groups, whereas the inter-regional component strongly prevails in the two Hindu samples and other Nepalese populations. The complete sequencing of mtDNAs from unresolved haplogroups also provided informative markers that greatly improved the mtDNA phylogeny and allowed the identification of ancient relationships between Tharus and Malaysia, the Andaman Islands and Japan as well as between India and North and East Africa. Overall, this study gives a paradigmatic example of the importance of genetic isolates in revealing variants not easily detectable in the general population.

KW - Indian Subcontinent

KW - malaria eradication

KW - indian component

KW - haplogroup frequency

KW - nepalese population

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DO - 10.1186/1471-2148-9-154

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