The Expanded mtDNA Phylogeny of the Franco-Cantabrian Region Upholds the Pre-Neolithic Genetic Substrate of Basques

Abstract

The European genetic landscape has been shaped by several human migrations occurred since Paleolithic times. The accumulation of archaeological records and the concordance of different lines of genetic evidence during the last two decades have triggered an interesting debate concerning the role of ancient settlers from the Franco-Cantabrian region in the postglacial resettlement of Europe. Among the Franco-Cantabrian populations, Basques are regarded as one of the oldest and more intriguing human groups of Europe. Recent data on complete mitochondrial DNA genomes focused on macrohaplogroup R0 revealed that Basques harbor some autochthonous lineages, suggesting a genetic continuity since pre-Neolithic times. However, excluding haplogroup H, the most representative lineage of macrohaplogroup R0, the majority of maternal lineages of this area remains virtually unexplored, so that further refinement of the mtDNA phylogeny based on analyses at the highest level of resolution is crucial for a better understanding of the European prehistory. We thus explored the maternal ancestry of 548 autochthonous individuals from various Franco-Cantabrian populations and sequenced 76 mitogenomes of the most representative lineages. Interestingly, we identified three mtDNA haplogroups, U5b1f, J1c5c1 and V22, that proved to be representative of Franco-Cantabria, notably of the Basque population. The seclusion and diversity of these female genetic lineages support a local origin in the Franco-Cantabrian area during the Mesolithic of southwestern Europe, ∼10,000 years before present (YBP), with signals of expansions at ∼3,500 YBP. These findings provide robust evidence of a partial genetic continuity between contemporary autochthonous populations from the Franco-Cantabrian region, specifically the Basques, and Paleolithic/Mesolithic hunter-gatherer groups. Furthermore, our results raise the current proportion (≈15%) of the Franco-Cantabrian maternal gene pool with a putative pre-Neolithic origin to ≈35%, further supporting the notion of a predominant Paleolithic genetic substrate in extant European populations.

Ancient mitochondrial lineages support the prehistoric maternal root of Basques in Northern Iberian Peninsula

“…Subhaplogroup H1j1, which only presents the polymorphism 16129A in the control region, was described by Behar et al 15 as an autochthonous haplogroup of the Franco-Cantabrian region. 15,16 This haplotype has been found with a remarkable frequency among numerous populations of the North of the Iberian Peninsula, especially in the Basque area, or in populations of Basque ancestry. 15,35,41,42 In this population sample of Busturialdea 18 individuals (11.39%) were classified into H1j1 subhaplogroup by the analysis of the coding region polymorphism T4733C.…”

“…It preserves autochthonous subhaplogroups rarely found out of this region, some of which have been described in the last years. 15,16,34,40 With the aim of studying the presence of the ancient mitochondrial lineages from past times in the present, the control region of mtDNA was analysed in a sample of 158 autochthonous Basque individuals belonging to the population inhabiting the vicinity of the Cave of Santimamiñe, the region of Busturialdea (Figure 1 Table S2) and descriptive statistics (Supplementary Table S3) of this population can be accessed in the Supplementary Material.…”

“…It represents 10% of the mitochondrial diversity of the current populations of the Franco-Cantabrian region, reaching a maximum frequency of ∼ 24% in the populations next to the Pyrenees and decreasing to the West. 16 Due to its frequency distribution pattern and its absence in populations out of the Franco-Cantabrian region, U5b1f1a was proposed as an autochthonous lineage of the Basque population, which could have originated during the Younger Dryas (12 800-11 500 years ago), with a splitting age of 11 985 years. 16 Comparison between ancient individuals of Santimamiñe and current population of Busturialdea To determine the presence of any kinship between past and present populations from Busturialdea, haplotypes of ancient samples from the Cave of Santimamiñe and current population of the area were studied all together by means of a neighbour-joining tree (Supplementary Figure S3).…”

“…13,14 These studies are grounded in the supposedly genetic continuity between the Palaeolithic huntergatherers and the autochthonous Basque population. 15,16 Herein we report a study on ancient maternal lineages of the Franco-Cantabrian region and their persistence in modern populations. It is based on the combination of ancient and modern mitochondrial DNA data.…”

New clues to the evolutionary history of the main European paternal lineage M269: dissection of the Y-SNP S116 in Atlantic Europe and Iberia

“…[2][3][4] Another theory, based on the variance of Y-STR haplotypes within M269, also supports its postglacial expansion but argues that M269 could have had a parallel expansion from a refuge in Eastern Europe (Anatolia). 5 The new theory proposed by Balaresque et al, 6 based on the higher diversity of Y-STR haplotypes in Eastern European M269 individuals than in Western European ones, concludes that there is a single origin for haplogroup M269 in Eastern Europe.…”