CTG Repeat Diversity at DMPK Gene Locus In Indian Population

India hasan extensive population admixture and genetic diversity of (CTG)n repeats. It is intriguing to investigate how different ethnic groups have a correlation with each other due to variability in (CTG)n repeats. Molecular evaluation of (CTG)n was performed on 400 individuals representing ethnic groups of North (Kayastha, Brahmin, Sunni, Shia, Vaishya, Chaturvedi) and North-East (Lachung and Mech) India. Population diversity analysis was made on the basis of phylogenetic, principal component analyses (PCA) and heat-map construction. Twenty three alleles (range 3-29 repeats) were detected when Indian subjects were pooled together. Kayastha, Brahmin, Sunni each showed 15 repeats as maximum percentage of common repeats, followed by Shia, Vaishya, Chaturvedi, Lachung and Mech respectively. Incidence for (CTG)>19repeats was 5.87% in pooled group of India. In comparison to Indians (47.29%), higher frequency of (CTG)9-18was concurred among Brazilians (100%) followed by North Americans (93.2%), Papua New Guineans (90%), Mexicans (86.2%) and Russians (83.4%). The North, North-East Indian populations form separate phylogenetic clades. However, Chaturvedis from mainland India formed a bridge between these two major population groups as evident from the dendrogram and genetic distance data. The PCA placed the North Indians, Caucasian and Mediterranean populations in one quartile and North-East Indian populations in the other. A bottleneck role of the north Eastern populations may be suggested as they serve as an inter-link between mainland India and Pacific/Australo-Malenesian populations from the human evolution perspective. In conclusion, our data provides an idea of (CTG)n repeat diversity in the studied Indian ethnic groups and their association with different ethnic and geographically isolated populations.