Inter-individual genomic heterogeneity within European population isolates

Abstract

28A number of studies carried out since the early '70s has investigated the effects of isolation on genetic 29 variation within and among human populations in diverse geographical contexts. However, no extensive 30 analysis has been carried out on the heterogeneity among genomes within isolated populations. This issue 31 is worth exploring since events of recent admixture and/or subdivision could potentially disrupt the 32 genetic homogeneity which is to be expected when isolation is prolonged and constant over time. Here, 33 we analyze literature data relative to 87,818 autosomal single-nucleotide polymorphisms, which were 34 obtained from a total of 28 European populations. Our results challenge the traditional paradigm of 35 population isolates as genetically (and genomically) uniform entities. In fact, focusing on the distribution 36 of variance of intra-population diversity measures across individuals, we show that the inter-individual 37 heterogeneity of isolated populations is at least comparable to the open ones. More in particular, three 38 small and highly inbred isolates (Sappada, Sauris and Timau in Northeastern Italy) were found to be 39 characterized by levels of this parameter largely exceeding that of all other populations, possibly due to 40 relatively recent events of genetic introgression. Finally, we propose a way to monitor the effects of inter-41 individual heterogeneity in disease-gene association studies. 42 43 the Cimbrians since it lacked consistent signatures of genetic isolation. Despite its limits [15], we maintain

Y‐chromosome variability and genetic history of Commons from Northern Italy

“…In other words, Commons appear as “open” to the rest of the population from the maternal side. This fact implies that, differently from “classic” isolates, such as ethno‐linguistic minorities as the Arbereshe of Southern Italy or German‐speaking groups from Northern Italy (Anagnostou et al, 2017; Anagnostou et al, 2019; Boattini et al, 2011; Coia et al, 2012; Coia et al, 2013; Colonna et al, 2013; Esko et al, 2013; Sarno et al, 2016), no inbreeding increase is expected in these populations, nor significant genetic differentiation, if autosomal variants or mitochondrial DNA (mtDNA) would have been considered. Indeed, no significant difference was observed in S. Giovanni in Persiceto between the Common and its Control from the mtDNA point of view (Boattini et al, 2015).…”