title: Genome-wide patterns of identity-by-descent sharing in the French Canadian founder population.
abstract: In genetics the ability to accurately describe the familial relationships among a group of individuals can be very useful. Recent statistical tools succeeded in assessing the degree of relatedness up to 6-7 generations with good power using dense genome-wide single-nucleotide polymorphism data to estimate the extent of identity-by-descent (IBD) sharing. It is therefore important to describe genome-wide patterns of IBD sharing for more remote and complex relatedness between individuals, such as that observed in a founder population like Quebec, Canada. Taking advantage of the extended genealogical records of the French Canadian founder population, we first compared different tools to identify regions of IBD in order to best describe genome-wide IBD sharing and its correlation with genealogical characteristics. Results showed that the extent of IBD sharing identified with FastIBD correlates best with relatedness measured using genealogical data. Total length of IBD sharing explained 85% of the genealogical kinship's variance. In addition, we observed significantly higher sharing in pairs of individuals with at least one inbred ancestor compared with those without any. Furthermore, patterns of IBD sharing and average sharing were different across regional populations, consistent with the settlement history of Quebec. Our results suggest that, as expected, the complex relatedness present in founder populations is reflected in patterns of IBD sharing. Using these patterns, it is thus possible to gain insight on the types of distant relationships in a sample from a founder population like Quebec.
authors.affiliation: 1] Département de médecine sociale et préventive, Université de Montréal, Montréal, Québec, Canada [2] Centre de recherche, Centre hospitalier universitaire Sainte-Justine, Université de Montréal, Montréal, Québec, Canada.
authors.forename: Héloïse
authors.initials: H
authors.lastname: Gauvin
authors.affiliation: Centre de recherche, Centre hospitalier universitaire Sainte-Justine, Université de Montréal, Montréal, Québec, Canada.
authors.forename: Claudia
authors.initials: C
authors.lastname: Moreau
authors.affiliation: Centre de recherche, Centre hospitalier universitaire Sainte-Justine, Université de Montréal, Montréal, Québec, Canada.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Lefebvre
authors.affiliation: Département des sciences fondamentales, Université du Québec à Chicoutimi, Chicoutimi, Québec, Canada.
authors.forename: Catherine
authors.initials: C
authors.lastname: Laprise
authors.affiliation: Département des sciences humaines, Université du Québec à Chicoutimi, Chicoutimi, Québec, Canada.
authors.forename: Hélène
authors.initials: H
authors.lastname: Vézina
authors.affiliation: 1] Centre de recherche, Centre hospitalier universitaire Sainte-Justine, Université de Montréal, Montréal, Québec, Canada [2] Département de pédiatrie, Université de Montréal, Montréal, Québec, Canada.
authors.forename: Damian
authors.initials: D
authors.lastname: Labuda
authors.affiliation: 1] Centre de recherche, Centre hospitalier universitaire Sainte-Justine, Université de Montréal, Montréal, Québec, Canada [2] Department of Epidemiology and Community Medicine, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Marie-Hélène
authors.initials: MH
authors.lastname: Roy-Gagnon
mesh_terms: D002170:Canada; D003241:Consanguinity; D018703:Founder Effect; D005602:France / Q000208:ethnology; D005789:Genealogy and Heraldry; D005828:Genetics, Population / Q000379:methods*; D055106:Genome-Wide Association Study / Q000379:methods*; D006239:Haplotypes; D006801:Humans; D020641:Polymorphism, Single Nucleotide