Browsing by Author "Federica Crivellaro"

Now showing 1 - 2 of 2

The Light Skin Allele of SLC24A5 in South Asians and Europeans Shares Identity by Descent
(2013) Chandana Basu Mallick; Florin Mircea Iliescu; Märt Möls; Sarah Hill; Rakesh Tamang; Gyaneshwer Chaubey; Rie Goto; Simon Y. W. Ho; Irene Gallego Romero; Federica Crivellaro; Georgi Hudjashov; Niraj Rai; Mait Metspalu; C. G. Nicholas Mascie-Taylor; Ramasamy Pitchappan; Lalji Singh; Marta Mirazon-Lahr; Kumarasamy Thangaraj; Richard Villems; Toomas Kivisild
Skin pigmentation is one of the most variable phenotypic traits in humans. A non-synonymous substitution (rs1426654) in the third exon of SLC24A5 accounts for lighter skin in Europeans but not in East Asians. A previous genome-wide association study carried out in a heterogeneous sample of UK immigrants of South Asian descent suggested that this gene also contributes significantly to skin pigmentation variation among South Asians. In the present study, we have quantitatively assessed skin pigmentation for a largely homogeneous cohort of 1228 individuals from the Southern region of the Indian subcontinent. Our data confirm significant association of rs1426654 SNP with skin pigmentation, explaining about 27% of total phenotypic variation in the cohort studied. Our extensive survey of the polymorphism in 1573 individuals from 54 ethnic populations across the Indian subcontinent reveals wide presence of the derived-A allele, although the frequencies vary substantially among populations. We also show that the geospatial pattern of this allele is complex, but most importantly, reflects strong influence of language, geography and demographic history of the populations. Sequencing 11.74 kb of SLC24A5 in 95 individuals worldwide reveals that the rs1426654-A alleles in South Asian and West Eurasian populations are monophyletic and occur on the background of a common haplotype that is characterized by low genetic diversity. We date the coalescence of the light skin associated allele at 22-28 KYA. Both our sequence and genome-wide genotype data confirm that this gene has been a target for positive selection among Europeans. However, the latter also shows additional evidence of selection in populations of the Middle East, Central Asia, Pakistan and North India but not in South India. © 2013 Basu Mallick et al.
Unravelling the distinct strains of Tharu ancestry
(Nature Publishing Group, 2014) Gyaneshwer Chaubey; Manvendra Singh; Federica Crivellaro; Rakesh Tamang; Amrita Nandan; Kamayani Singh; Varun Kumar Sharma; Ajai Kumar Pathak; Anish M. Shah; Vishwas Sharma; Vipin Kumar Singh; Deepa Selvi Rani; Niraj Rai; Alena Kushniarevich; Anne-Mai Ilumäe; Monika Karmin; Anand Phillip; Abhilasha Verma; Erik Prank; Vijay Kumar Singh; Blaise Li; Periyasamy Govindaraj; Akhilesh Kumar Chaubey; Pavan Kumar Dubey; Alla G. Reddy; Kumpati Premkumar; Satti Vishnupriya; Veena Pande; Jüri Parik; Siiri Rootsi; Phillip Endicott; Mait Metspalu; Marta Mirazon Lahr; George Van Driem; Richard Villems; Toomas Kivisild; Lalji Singh; Kumarasamy Thangaraj
The northern region of the Indian subcontinent is a vast landscape interlaced by diverse ecologies, for example, the Gangetic Plain and the Himalayas. A great number of ethnic groups are found there, displaying a multitude of languages and cultures. The Tharu is one of the largest and most linguistically diverse of such groups, scattered across the Tarai region of Nepal and bordering Indian states. Their origins are uncertain. Hypotheses have been advanced postulating shared ancestry with Austroasiatic, or Tibeto-Burman-speaking populations as well as aboriginal roots in the Tarai. Several Tharu groups speak a variety of Indo-Aryan languages, but have traditionally been described by ethnographers as representing East Asian phenotype. Their ancestry and intra-population diversity has previously been tested only for haploid (mitochondrial DNA and Y-chromosome) markers in a small portion of the population. This study presents the first systematic genetic survey of the Tharu from both Nepal and two Indian states of Uttarakhand and Uttar Pradesh, using genome-wide SNPs and haploid markers. We show that the Tharu have dual genetic ancestry as up to one-half of their gene pool is of East Asian origin. Within the South Asian proportion of the Tharu genetic ancestry, we see vestiges of their common origin in the north of the South Asian Subcontinent manifested by mitochondrial DNA haplogroup M43. © 2014 Macmillan Publishers Limited All rights reserved.