The Phylogeography of Y-Chromosome Haplogroup H1a1a-M82 Reveals the Likely Indian Origin of the European Romani Populations

Abstract

Linguistic and genetic studies on Roma populations inhabited in Europe have unequivocally traced these populations to the Indian subcontinent. However, the exact parental population group and time of the out-of-India dispersal have remained disputed. In the absence of archaeological records and with only scanty historical documentation of the Roma, comparative linguistic studies were the first to identify their Indian origin. Recently, molecular studies on the basis of disease-causing mutations and haploid DNA markers (i.e. mtDNA and Y-chromosome) supported the linguistic view. The presence of Indian-specific Y-chromosome haplogroup H1a1a-M82 and mtDNA haplogroups M5a1, M18 and M35b among Roma has corroborated that their South Asian origins and later admixture with Near Eastern and European populations. However, previous studies have left unanswered questions about the exact parental population groups in South Asia. Here we present a detailed phylogeographical study of Y-chromosomal haplogroup H1a1a-M82 in a data set of more than 10,000 global samples to discern a more precise ancestral source of European Romani populations. The phylogeographical patterns and diversity estimates indicate an early origin of this haplogroup in the Indian subcontinent and its further expansion to other regions. Tellingly, the short tandem repeat (STR) based network of H1a1a-M82 lineages displayed the closest connection of Romani haplotypes with the traditional scheduled caste and scheduled tribe population groups of northwestern India.

Reconstructing Roma History from Genome-Wide Data

“…First, a study based on Y-chromosome haplogroups showed that on the paternal lineage, Roma haplotypes cluster predominantly with the Northwestern Indian haplotypes [26], consistent with our findings based on autosomal IBD sharing. The second study was based on whole genome SNP genotype data like ours [27].…”

A genetic chronology for the Indian Subcontinent points to heavily sex-biased dispersals

“…2a) appears at low levels in Iran. As an aside, the bulk of Romani lineages belongs to the branch M5a1b1a1 [70] at 3.0 ka, supporting previous linguistic and genetic evidence for a South Asian origin for the Romani diaspora [70, 71] in the west of the Subcontinent.

Fig. 2 a ADMIXTURE analysis for K  = 7. b PCA of South Asian populations.

…”

Unity in diversity: an overview of the genomic anthropology of India

“…A large number of research papers have documented mtDNA and Y-chromosome variation among Indian populations (Bamshad et al 2001;Kivisild et al 1999Kivisild et al , 2003Corduex et al 2003;Basu et al 2003;Palanichamy et al 2004;Sengupta et al 2006;Sahoo et al 2006;Gutala et al 2006;Thanseem et al 2006;Zerjal et al 2007 ;Thangaraj et al 2006a, b;Sengupta et al 2006;Chaubey et al 2008;Mittal el al. 2008;Eaaswarkhanth et al 2010;Chaubey et al 2011;Debnath et al 2011;Wang et al 2011;Rai et al 2012;Chaubey et al 2014). Barnabas et al (1996) was one of the earliest studies, using low resolution mtDNA analysis among linguistically different Indian populations to document a high level of nucleotide diversity among Indians.…”