Genome-wide analysis of Corsican population reveals a close affinity with Northern and Central Italy

Abstract

Despite being the fourth largest island in the Mediterranean basin, the genetic variation of Corsica has not been explored as exhaustively as Sardinia, which is situated only 11 km South. However, it is likely that the populations of the two islands shared, at least in part, similar demographic histories. Moreover, the relative small size of the Corsica may have caused genetic isolation, which, in turn, might be relevant under medical and translational perspectives. Here we analysed genome wide data of 16 Corsicans, and integrated with newly (33 individuals) and previously generated samples from West Eurasia and North Africa. Allele frequency, haplotype-based, and ancient genome analyses suggest that although Sardinia and Corsica may have witnessed similar isolation and migration events, the latter is genetically closer to populations from continental Europe, such as Northern and Central Italians.

Y-chromosome and Surname Analyses for Reconstructing Past Population Structures: The Sardinian Population as a Test Case

“…The populations of the Italian Peninsula and the Mediterranean islands follow a North-South cline with the northern-central Italians (together with Corsicans) closer to Spanish and French groups while the southern central Italians (and Sicilians) are closer to Caucasus-Anatolian and middle eastern populations. A similar pattern is also detected when looking at the entire genome, with Corsicans closer to the Central-North Italian groups [25], and Sicilians to Central-South Italian populations [5]. Conversely Sardinians, who strongly behave as outliers at the genomic level [5], appear located at a fringe of the Western European distribution of Y-chromosome variation.…”

“…Genome-wide analyses of modern DNA place Sardinian samples in an outlier position in the European genomic landscape [2,5,25,74,75,76] strongly mirroring the outcome of genomic analyses of early European Neolithic farmers [26,27]. The peculiarity of modern Sardinians is confirmed by the analysis of Y-chromosome haplogroup frequencies.…”

“…In spite of this continuous chain of invasions, the gene flow into the Sardinian population has been relevant only in some coastal areas where well-known foreign settlements took place [15]. As a result, the ancient origin of native Sardinians and their long-standing isolation might provide an explanation for their genetic peculiarity [16], characterized by high frequencies of uniparental haplotypes that are rare elsewhere in Europe [2,17,18,19,20,21,22,23], extensive linkage disequilibrium of autosomal markers [24], as well as high degrees of homozygosity at the genomic level [25].…”

The mitogenome portrait of Umbria in Central Italy as depicted by contemporary inhabitants and pre-Roman remains

“…Concerning the phylogeography of Italy, it is difficult to identify a clear genetic pattern able to discriminate southern, northern and central populations in spite of several attempts based on autosomal and uniparental markers [19][20][21][22][23][24] . Southern populations were mostly influenced by Greek and Arab colonizations, Northern Italians might reflect admixture with French and German-speaking populations, while Central Italy occupies its own intermediate position creating a continuous cline of variation across the peninsula (with Sardinians as outliers) 13,19,[25][26][27][28][29] . Most of these studies were performed on a large geographic scale producing low-definition results and mainly focusing on modern populations.…”

Population genomics of Corsican wildcats: Paving the way toward a new subspecies within the Felis silvestris spp. complex?

“…Through time, Sardinia and Corsica have shared a large part of their history, being one single landmass during the last glaciation but also sharing similar history of colonization by humans and genetic ancestry (Grimaldi et al, 2001; Tamm et al, 2019 and references therein). A high phylogenetic proximity has also been evidenced for several species they host (e.g., mouflon, Portanier, Chevret, et al, 2022; weasel Mustela nivalis , Lebarbenchon et al, 2010; Corsican red deer C ervus elaphus corsicanus , Doan et al, 2017).…”