MtDNA polymorphisms among Tharus of eastern Terai (Nepal)

Area of Science:

• Anthropology
• Population Genetics
• Human Evolution

Background:

• The Tharu people of the Terai region have historically been considered a single Mongoloid population.
• Previous studies indicated high frequencies of alpha-thal gene in Western and Central Tharus, but unexpectedly low in Eastern Tharus, questioning their unified identity.

Purpose of the Study:

• To investigate the anthropological status of Eastern Tharus using mitochondrial DNA (mtDNA) markers.
• To clarify whether Tharus represent a single anthropological entity or distinct subgroups.

Main Methods:

• Analysis of mtDNA markers (HpaI, HincII, HaeII, BamHI polymorphisms) in Eastern Tharu samples.
• Comparison of mtDNA data with existing genetic and anthropological data from Central Tharus and neighboring populations.

Main Results:

• Eastern Tharus exhibit Mongoloid mtDNA features (HpaI-1/HincII-1, HaeII-5 morphs, lack of BamHI polymorphism), supporting their classification as a single anthropological entity.
• Significant genetic differences, including HaeII morph 5 frequency and a specific mtDNA mutation (15.487 bp), were found between Eastern and Central Tharus.
• Combined with alpha-thal gene data, these genetic variations suggest effective reproductive isolation among Tharu subgroups.

Conclusions:

• The Tharu population, despite subgroup variations, is supported as a single anthropological entity based on mtDNA markers.
• Genetic divergence between Eastern and Central Tharus points to a history of reproductive isolation, influencing their distinct genetic profiles.