Genomic history of the Italian population recapitulates key evolutionary dynamics of both Continental and Southern Europeans

Marco Sazzini, Paolo Abondio, Stefania Sarno, Guido Alberto Gnecchi-Ruscone, Matteo Ragno, Cristina Giuliani, Sara De Fanti, Claudia Ojeda-Granados, Alessio Boattini, Julien Marquis, Armand Valsesia, Jerome Carayol, Frederic Raymond, Chiara Pirazzini, Elena Marasco, Alberto Ferrarini, Luciano Xumerle, Sebastiano Collino, Daniela Mari, Beatrice ArosioDaniela Monti, Giuseppe Passarino, Patrizia D'Aquila, Davide Pettener, Donata Luiselli, Gastone Castellani, Massimo Delledonne, Patrick Descombes, Claudio Franceschi, Paolo Garagnani

Research output: Contribution to journalArticlepeer-review

Abstract

Background: The cline of human genetic diversity observable across Europe is recapitulated at a micro-geographic scale by variation within the Italian population. Besides resulting from extensive gene flow, this might be ascribable also to local adaptations to diverse ecological contexts evolved by people who anciently spread along the Italian Peninsula. Dissecting the evolutionary history of the ancestors of present-day Italians may thus improve the understanding of demographic and biological processes that contributed to shape the gene pool of European populations. However, previous SNP array-based studies failed to investigate the full spectrum of Italian variation, generally neglecting low-frequency genetic variants and examining a limited set of small effect size alleles, which may represent important determinants of population structure and complex adaptive traits. To overcome these issues, we analyzed 38 high-coverage whole-genome sequences representative of population clusters at the opposite ends of the cline of Italian variation, along with a large panel of modern and ancient Euro-Mediterranean genomes. Results: We provided evidence for the early divergence of Italian groups dating back to the Late Glacial and for Neolithic and distinct Bronze Age migrations having further differentiated their gene pools. We inferred adaptive evolution at insulin-related loci in people from Italian regions with a temperate climate, while possible adaptations to pathogens and ultraviolet radiation were observed in Mediterranean Italians. Some of these adaptive events may also have secondarily modulated population disease or longevity predisposition. Conclusions: We disentangled the contribution of multiple migratory and adaptive events in shaping the heterogeneous Italian genomic background, which exemplify population dynamics and gene-environment interactions that played significant roles also in the formation of the Continental and Southern European genomic landscapes.

Original languageEnglish
Article number51
JournalBMC Biology
Volume18
Issue number1
DOIs
Publication statusPublished - May 22 2020

Keywords

  • Demographic inference
  • Evolutionary medicine
  • Italian population
  • Polygenic adaptation
  • Whole-genome sequences

ASJC Scopus subject areas

  • Biotechnology
  • Structural Biology
  • Ecology, Evolution, Behavior and Systematics
  • Physiology
  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)
  • Plant Science
  • Developmental Biology
  • Cell Biology

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