Genetic origins, singularity, and heterogeneity of Basques

• Published in: Current biology Vol. 31; no. 10; pp. 2167 - 2177.e4
• Main Authors: Flores-Bello, André, Bauduer, Frédéric, Salaberria, Jasone, Oyharçabal, Bernard, Calafell, Francesc, Bertranpetit, Jaume, Quintana-Murci, Lluis, Comas, David
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 24-05-2021; Elsevier
• Subjects: Basques; demographic history; Euskara; Franco-Cantabrian; Gene Frequency; Genetic Variation; Genetics; Genetics, Population; genome-wide data; Geography; Haplotypes; Human genetics; Humans; isolated population; Life Sciences; population structure; Spain; Whites; Spain; Euskara; population structure; demographic history; genome-wide data; Franco-Cantabrian; isolated population; Basques
• ISSN: 0960-9822; 1879-0445
• DOI: 10.1016/j.cub.2021.03.010

Basques have historically lived along the Western Pyrenees, in the Franco-Cantabrian region, straddling the current Spanish and French territories. Over the last decades, they have been the focus of intense research due to their singular cultural and biological traits that, with high controversy, placed them as a heterogeneous, isolated, and unique population. Their non-Indo-European language, Euskara, is thought to be a major factor shaping the genetic landscape of the Basques. Yet there is still a lively debate about their history and assumed singularity due to the limitations of previous studies. Here, we analyze genome-wide data of Basque and surrounding groups that do not speak Euskara at a micro-geographical level. A total of ∼629,000 genome-wide variants were analyzed in 1,970 modern and ancient samples, including 190 new individuals from 18 sampling locations in the Basque area. For the first time, local- and wide-scale analyses from genome-wide data have been performed covering the whole Franco-Cantabrian region, combining allele frequency and haplotype-based methods. Our results show a clear differentiation of Basques from the surrounding populations, with the non-Euskara-speaking Franco-Cantabrians located in an intermediate position. Moreover, a sharp genetic heterogeneity within Basques is observed with significant correlation with geography. Finally, the detected Basque differentiation cannot be attributed to an external origin compared to other Iberian and surrounding populations. Instead, we show that such differentiation results from genetic continuity since the Iron Age, characterized by periods of isolation and lack of recent gene flow that might have been reinforced by the language barrier.
•Clear genetic singularity of Basques is observed at wide- and fine-scale levels•Basque differentiation might lie on the absence of gene flow after the Iron Ages•Genetic substructure correlated with geography and linguistics is detected
Flores-Bello et al. study the genetics of Basques with unprecedented geographical coverage and haplotype methods. They share common origin with their neighbors, but a lack of gene flow since the Iron Ages has modeled their uniqueness and heterogeneity. These barriers coincide with language limits, suggesting their role in the present genetics of Basques.