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Variabilità genetica del cromosoma Y in Sardegna: implicazioni negli studi di associazione sulle malattie multifattoriali.

Contu, Daniela (2007) Variabilità genetica del cromosoma Y in Sardegna: implicazioni negli studi di associazione sulle malattie multifattoriali. [Doctoral Thesis]

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Abstract

The island of Sardinia shows a unique high incidence of several autoimmune diseases with multifactorial inheritance, particularly type 1 diabetes and multiple sclerosis. The prior knowledge of the genetic structure of this population is fundamental to establish the optimal design for association studies in these diseases. Previous work suggested that the Sardinians are a relatively homogenous population, but some reports were contradictory and data were largely based on variants subject to selection. For an unbiased assessment of genetic structure, we studied a combination of neutral Y-chromosome variants, 21 biallelic and 8 short tandem repeats (STRs) in 930 Sardinian males. We found a high degree of interindividual variation but a homogenous distribution of the detected variability in samples from three separate regions of the island. One haplogroup, I-M26, is rare or absent outside Sardinia and is very common (0.37 frequency) throughout the island, consistent with a founder effect. A Bayesian full likelihood analysis (BATWING) indicated that the time from the most recent common ancestor (TMRCA) of I-M26, was 21.0 (16.0-25.5) thousand years ago (KYA) and that the population began to expand 14.0 (7.8-22.0) KYA. These results suggest a largely pre-Neolithic settlement of the island with little subsequent gene flow from outside populations. Consequently, Sardinia is an especially attractive venue for case-control genome wide association scans in common multifactorial diseases. Concomitantly, the high degree of interindividual variation in the current population facilitates fine mapping efforts to pinpoint the aetiologic polymorphisms.

Item Type:Doctoral Thesis
Date:14 December 2007
Tutor:Cucca, Francesco
PhD classes:Ciclo 20 > Terapia pediatrica e farmacologia dello sviluppo
Institution:Universita' degli Studi di Cagliari
Divisions:Dipartimenti (fino a dicembre 2011) > Dipartimento di Scienze biomediche e biotecnologie
Subjects:Area 06 - Scienze mediche > MED/03 Genetica medica
Uncontrolled Keywords:Y chromosome, Sardinia.
ID Code:25
Deposited On:27 Oct 2008 11:32

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