“…Multivariate analyses (also called ordinations in reduced space) such as principal component analysis (Pearson, 1901) have been shown to be efficient in extracting information from genetic markers (CavalliSforza, 1966;Johnson et al, 1969;Smouse et al, 1982) because of their ability to summarize multivariate genetic information into a few synthetic variables. From these early applications to current innovative developments Pavoine and Bailly, 2007;Jombart et al, 2008), these methods have proven to be useful in various fields, such as human genetics (Menozzi et al, 1978;Bertranpetit and Cavalli-Sforza, 1991;Cavalli-Sforza et al, 1993), conservation (MoazamiGoudarzi et al, 1997;Escudero et al, 2003;Laloë et al, 2007), phylogeography (Hanotte et al, 2002;Matsuoka et al, 2002;Ciofi et al, 2006), landscape genetics (Angers et al, 1999;McRae et al, 2005) and the identification of adaptations (Johnson et al, 1969;Mulley et al, 1979;Barker et al, 1986).…”