High Differentiation among Eight Villages in a Secluded Area of Sardinia Revealed by Genome-Wide High Density SNPs Analysis

Giorgio Pistis*, Ignazio Piras, Nicola Pirastu, Ivana Persico, Alessandro Sassu, Andrea Picciau, Dionigio Prodi, Cristina Fraumene, Evelina Mocci, Maria Teresa Manias, Rossano Atzeni, Massimiliano Cosso, Mario Pirastu, Andrea Angius

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

To better design association studies for complex traits in isolated populations it's important to understand how history and isolation moulded the genetic features of different communities. Population isolates should not "a priori" be considered homogeneous, even if the communities are not distant and part of a small region. We studied a particular area of Sardinia called Ogliastra, characterized by the presence of several distinct villages that display different history, immigration events and population size. Cultural and geographic isolation characterized the history of these communities. We determined LD parameters in 8 villages and defined population structure through high density SNPs (about 360 K) on 360 unrelated people (45 selected samples from each village). These isolates showed differences in LD values and LD map length. Five of these villages show high LD values probably due to their reduced population size and extreme isolation. High genetic differentiation among villages was detected. Moreover population structure analysis revealed a high correlation between genetic and geographic distances. Our study indicates that history, geography and biodemography have influenced the genetic features of Ogliastra communities producing differences in LD and population structure. All these data demonstrate that we can consider each village an isolate with specific characteristics. We suggest that, in order to optimize the study design of complex traits, a thorough characterization of genetic features is useful to identify the presence of sub-populations and stratification within genetic isolates.

Original languageEnglish
Article number4654
Number of pages12
JournalPLoS ONE
Volume4
Issue number2
DOIs
Publication statusPublished - 27 Feb 2009

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