title: Sardinians genetic background explained by runs of homozygosity and genomic regions under positive selection.
abstract: The peculiar position of Sardinia in the Mediterranean sea has rendered its population an interesting biogeographical isolate. The aim of this study was to investigate the genetic population structure, as well as to estimate Runs of Homozygosity and regions under positive selection, using about 1.2 million single nucleotide polymorphisms genotyped in 1077 Sardinian individuals. Using four different methods--fixation index, inflation factor, principal component analysis and ancestry estimation--we were able to highlight, as expected for a genetic isolate, the high internal homogeneity of the island. Sardinians showed a higher percentage of genome covered by RoHs>0.5 Mb (F(RoH%0.5)) when compared to peninsular Italians, with the only exception of the area surrounding Alghero. We furthermore identified 9 genomic regions showing signs of positive selection and, we re-captured many previously inferred signals. Other regions harbor novel candidate genes for positive selection, like TMEM252, or regions containing long non coding RNA. With the present study we confirmed the high genetic homogeneity of Sardinia that may be explained by the shared ancestry combined with the action of evolutionary forces.
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy; HuGeF Human Genetics Foundation, Turin, Italy.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Di Gaetano
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy; HuGeF Human Genetics Foundation, Turin, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Fiorito
authors.affiliation: Hypertension and Related Diseases Center, AOU, University of Sassari, Sassari, Italy.
authors.forename: Maria Francesca
authors.initials: MF
authors.lastname: Ortu
authors.affiliation: HuGeF Human Genetics Foundation, Turin, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Rosa
authors.affiliation: HuGeF Human Genetics Foundation, Turin, Italy.
authors.forename: Simonetta
authors.initials: S
authors.lastname: Guarrera
authors.affiliation: HuGeF Human Genetics Foundation, Turin, Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Pardini
authors.affiliation: Department of Health Sciences, University of Milan, Milan, Italy; Filarete Foundation, Genomic and Bioinformatics Unit, Viale Ortles 22/4, Milan, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Cusi
authors.affiliation: Hypertension and Related Diseases Center, AOU, University of Sassari, Sassari, Italy; Department of Health Sciences, University of Milan, Milan, Italy; Filarete Foundation, Genomic and Bioinformatics Unit, Viale Ortles 22/4, Milan, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Frau
authors.affiliation: Department of Health Sciences, University of Milan, Milan, Italy; Filarete Foundation, Genomic and Bioinformatics Unit, Viale Ortles 22/4, Milan, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Barlassina
authors.affiliation: Hypertension and Related Diseases Center, AOU, University of Sassari, Sassari, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Troffa
authors.affiliation: Hypertension and Related Diseases Center, AOU, University of Sassari, Sassari, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Argiolas
authors.affiliation: Hypertension and Related Diseases Center, AOU, University of Sassari, Sassari, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Zaninello
authors.affiliation: Hypertension and Related Diseases Center, AOU, University of Sassari, Sassari, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Fresu
authors.affiliation: Hypertension and Related Diseases Center, AOU, University of Sassari, Sassari, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Glorioso
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy; HuGeF Human Genetics Foundation, Turin, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Piazza
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy; HuGeF Human Genetics Foundation, Turin, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Matullo
mesh_terms: D020029:Base Pairing / Q000235:genetics; D015894:Genome, Human / Q000235:genetics*; D005843:Geography; D006720:Homozygote; D006801:Humans; D007178:Inbreeding; D007558:Italy; D008522:Mediterranean Sea; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D025341:Principal Component Analysis; D012641:Selection, Genetic; D012984:Software