Reconstructing the Population History of European Romani from Genome-wide Data

Abstract

The Romani, the largest European minority group with approximately 11 million people, constitute a mosaic of languages, religions, and lifestyles while sharing a distinct social heritage. Linguistic and genetic studies have located the Romani origins in the Indian subcontinent. However, a genome-wide perspective on Romani origins and population substructure, as well as a detailed reconstruction of their demographic history, has yet to be provided. Our analyses based on genome-wide data from 13 Romani groups collected across Europe suggest that the Romani diaspora constitutes a single initial founder population that originated in north/northwestern India ~1.5 thousand years ago (kya). Our results further indicate that after a rapid migration with moderate gene flow from the Near or Middle East, the European spread of the Romani people was via the Balkans starting ~0.9 kya. The strong population substructure and high levels of homozygosity we found in the European Romani are in line with genetic isolation as well as differential gene flow in time and space with non-Romani Europeans. Overall, our genome-wide study sheds new light on the origins and demographic history of European Romani.

Origins, admixture and founder lineages in European Roma

“…We searched for matches of M-haplotypes present in European Roma within India, under the assumption that all the European Roma originated from the same region. The highest probability for the mtDNA in Roma populations was found in NW India (P = 0.713; Table 2), in agreement with previous studies, 6,7,9 linguistic, anthropological, and historical evidences. 1 The evolution of the population size through time was modeled for the M-lineages in a BSP (Supplementary Figure S4), assuming that these lineages will reveal the demographic history of the proto-Roma population before its arrival into Europe.…”

“…We expected a bottleneck signal by the time of the diaspora from India as recently shown for autosomal markers. 6 Surprisingly, no signal of founder effect was detected. Otherwise, the BSP showed an increase in Ne starting 3-4 ky ago, which coincides with the expansion of the Indo-European languages in North India.…”

“…1,2 Based on linguistic, cultural, anthropological, and genetic evidence, the proto-Roma population is thought to have originated on the Indian subcontinent. 1,[3][4][5][6][7][8][9] Their migration routes probably encompassed Persia, Armenia, and the Balkans, with a large consensus on their arrival in Eastern Europe around a thousand years ago. Within a period of about two centuries, most Roma became sedentary in the Balkan Peninsula (Balkan Roma), in the relatively ethnically tolerant surroundings of the newly established Ottoman Empire.…”

“…25,26,27 Accordingly, studies of autosomal markers identified the Northwest of India as the most probable homeland of the European Roma. 6 Despite these previous genetic studies, the Roma demographic history remains poorly understood. Y-chromosome and mtDNA lineages other than H and the M major haplogroups, respectively, have been attributed to genetic influences from populations along the proto-Roma migration way 7,21 without a more specific definition of their geographic origins.…”

Genetic and biochemical study of dual hereditary jaundice: Dubin–Johnson and Gilbert’s syndromes. Haplotyping and founder effect of deletion in ABCC2

“…A great majority of European Roma shares the same haplotypes -haplogroup H-M82 of chromosome Y and mitochondrial haplogroup M. Their common ancestors originate 1500 years ago from Northern India. [15][16][17] In this work, we investigated the prevalence of dual hereditary jaundice among 56 members from seven seemingly unrelated Roma families. Here we report the identification of a novel variant in ABCC2 gene together with a compound defect in ABCC2 and UGT1A1 genes and a shared haplotype among all seven families.…”