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The Finnish population is a unique example of a genetic isolate affected by a recent founder event. Previous studies have suggested that the ancestors of Finnic-speaking Finns and Estonians reached the circum-Baltic region by the 1(st) millennium BC. However, high linguistic similarity points to a more recent split of their languages. To study genetic connectedness between Finns and Estonians directly, we first assessed the efficacy of imputation of low-coverage ancient genomes by sequencing a medieval Estonian genome to high depth (23×) and evaluated the performance of its down-sampled replicas. We find that ancient genomes imputed from >0.1× coverage can be reliably used in principal-component analyses without projection. By searching for long shared allele intervals (LSAIs; similar to identity-by-descent segments) in unphased data for >143,000 present-day Estonians, 99 Finns, and 14 imputed ancient genomes from Estonia, we find unexpectedly high levels of individual connectedness between Estonians and Finns for the last eight centuries in contrast to their clear differentiation by allele frequencies. High levels of sharing of these segments between Estonians and Finns predate the demographic expansion and late settlement process of Finland. One plausible source of this extensive sharing is the 8(th)–10(th) centuries AD migration event from North Estonia to Finland that has been proposed to explain uniquely shared linguistic features between the Finnish language and the northern dialect of Estonian and shared Christianity-related loanwords from Slavic. These results suggest that LSAI detection provides a computationally tractable way to detect fine-scale structure in large cohorts.

Unlike other European countries, the human population genetics and demographic history of Metropolitan France is surprisingly understudied. In this work, we combined newly genotyped samples from various zones in France with publicly available data and applied both allele frequency and haplotype-based methods to describe the internal structure of this country, using genome-wide single nucleotide polymorphism (SNP) array genotypes. We found out that French Basques, already known for their linguistic uniqueness, are genetically distinct from all other groups and that the populations from southwest France (namely the Gascony region) share a large proportion of their ancestry with Basques. Otherwise, the genetic makeup of the French population is relatively homogeneous and mostly related to Southern and Central European groups. However, a fine-grained, haplotype-based analysis revealed that Bretons slightly separated from the rest of the groups, due mostly to gene flow from the British Isles in a time frame that coincides both historically attested Celtic population movements to this area between the 3th and the ninth centuries CE, but also with a more ancient genetic continuity between Brittany and the British Isles related to the shared drift with hunter-gatherer populations. Haplotype-based methods also unveiled subtle internal structures and connections with the surrounding modern populations, particularly in the periphery of the country., Funding was provided by the Agencia Estatal de Investigación and Fondo Europeo de Desarollo Regional (FEDER) (grant CGL2016-75389-P), Agència de Gestió d’Ajuts Universitaris i de la Recerca (Generalitat de Catalunya) Grant 2014SGR2866, and “Unidad de Excelencia María de Maeztu”, funded by the MINECO (ref: MDM-2014–0370). SAB was supported by the Agencia Estatal de Investigación FPI grant BES-2014–069224.

Poster presented at the Human Evolution, held between 30th Octuber and 1st November in 2019, in Cambridge (UK)., Unlike other European countries, Metropolitan France is surprisingly understudied. We have combined newly genotyped samples from various zones in France with publicly available data and applied both allele frequency and haplotype-based methods in order to describe the internal structure of this country, taking advantage of the Human Origins SNP array, specifically designed for human population genetics studies. We found out that French Basques are genetically distinct from all other populations in the Hexagone and that the populations from southwest France (namely the Franco-Cantabrian region) are intermediate between Basques and other populations. Moreover, Bretons slightly separated from the rest of the groups and a link with the historical gene flow from the British Isles has been found. Results from the allele frequency analyses point to a general background that appears to be a mixture of two components, one closer to Southern Italy and the other to Ireland. This combination may be the result of a contact that happened in two different moments: in the Early Neolithic, and then Ireland would be a proxy for the continental pathway for the Neolithic wave of advance and South Italy for the coastal penetration, or the Iron Age, when the Celtic and the Mediterranean worlds met in France. On the other hand, results from the haplotype-based methods describe a more structured landscape, highlighting the presence of areas characterized by differential links with the neighboring populations, possibly reflecting a more recent history.

In this study, we seek to understand and to correlate the genetic patterns observed in the population of the island of Ibiza in the Western Mediterranean basin with past events. Genome-wide genotypes of 189 samples representing 13 of 17 regions in Spain have been analyzed, in addition to 105 samples from the Levant, 157 samples from North Africa, and one ancient sample from the Phoenician Cas Molí site in Ibiza. Before the Catalans conquered the island in 1235 CE, Ibiza (Eivissa) had already been influenced by several cultures, starting with the Phoenicians, then the Carthaginians, followed by the Umayyads. The impact of these various cultures on the genetic structure of the islanders is still unexplored. Our results show a clear distinction between Ibiza and the rest of Spain. To investigate whether this was due to the Phoenician colonization or to more recent events, we compared the genomes of current Ibizans to that of an ancient Phoenician sample from Ibiza and to both modern Levantine and North African genomes. We did not identify any trace of Phoenician ancestry in the current Ibizans. Interestingly, the analysis of runs of homozygosity and changes in the effective population size through time support the idea that drift has shaped the genetic structure of current Ibizans. In addition to the small carrying capacity of the island, Ibiza experienced a series of dramatic demographic changes due to several instances of famine, war, malaria and plague that could have significantly contributed to its current genetic differentiation., Funding was provided by the Agencia Estatal de Investigación and Fondo Europeo de Desarollo Regional (FEDER) (grant CGL2016-75389-P), Agència de Gestió d’Ajuts Universitaris i de la Recerca (Generalitat de Catalunya) grant 2014 SGR 866, and “Unidad de Excelencia María de Maeztu”, funded by the MINECO (ref: MDM-2014-0370). SAB was supported by the Agencia Estatal de Investigación FPI grant BES-2014-069224.