European Roma groups show complex West Eurasian admixture footprints and a common South Asian genetic origin

Abstract

The Roma population is the largest transnational ethnic minority in Europe, characterized by a linguistic, cultural and historical heterogeneity. Comparative linguistics and genetic studies have placed the origin of European Roma in the Northwest of India. After their migration across Persia, they entered into the Balkan Peninsula, from where they spread into Europe, arriving in the Iberian Peninsula in the 15th century. Their particular demographic history has genetic implications linked to rare and common diseases. However, the South Asian source of the proto-Roma remains still untargeted and the West Eurasian Roma component has not been yet deeply characterized. Here, in order to describe both the South Asian and West Eurasian ancestries, we analyze previously published genome-wide data of 152 European Roma and 34 new Iberian Roma samples at a fine-scale and haplotype-based level, with special focus on the Iberian Roma genetic substructure. Our results suggest that the putative origin of the proto-Roma involves a Punjabi group with low levels of West Eurasian ancestry. In addition, we have identified a complex West Eurasian component (around 65%) in the Roma, as a result of the admixture events occurred with non-proto-Roma populations between 1270–1580. Particularly, we have detected the Balkan genetic footprint in all European Roma, and the Baltic and Iberian components in the Northern and Western Roma groups, respectively. Finally, our results show genetic substructure within the Iberian Roma, with different levels of West Eurasian admixture, as a result of the complex historical events occurred in the Peninsula.

The shaping of immunological responses through natural selection after the Roma Diaspora

“…Applying the f4 ratio estimation, we estimated this admixture to be between 48-54% (Supplementary Table 6). Roma groups from the Balkan Peninsula and Central Europe tend to have lower West Eurasian ancestry than other Roma groups 16,22 .…”

“…It has been suggested that the West Eurasian ancestry present within India, and mainly in the North, increases the genetic similarity of the Roma with other European populations 3,14 . This, together with the influx of European migrants into a population with small effective size and the high genetic drift of the Roma subgroups, make the Roma more genetically similar to European than to South Asian populations 16 .…”

“…www.nature.com/scientificreports/ different Roma groups, further narrowed the putative population of origin of the proto-Roma to inhabit the Northwestern region of the Indian subcontinent 2,12,[14][15][16] .…”

Roma Health: An Overview of Communicable Diseases in Eastern and Central Europe

“…They began their migration westwards between the 6th to 10th century, with groups settling along the way, finally entering Europe in the 12th century. Roma communities across Europe and Central Asia gradually formed diverse endogamous sub-groupings, still retaining large parts of their language and culture [ 1 , 2 ]. In Europe alone they now number around 11 million, the vast majority living in Eastern and Central Europe ( Table S1 ).…”

Social Structure in a Roma Settlement: Comparison over Time

“…The Roma population is the largest transnational ethnic minority in Europe, characterized by linguistic [ 1 , 2 , 3 ], cultural [ 4 , 5 ] and historical heterogeneity [ 6 , 7 , 8 ]. Roma are thus not a single, homogeneous group of people [ 9 , 10 , 11 , 12 , 13 ].…”