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International audience; Background: The HapMap samples were collected for medical-genetic studies, but are also widely used in populationgenetic and evolutionary investigations. Yet the ascertainment of the samples differs from most population-genetic studies which collect individuals who live in the same local region as their ancestors. What effects could this non-standard ascertainment have on the interpretation of HapMap results? Methodology/Principal Findings: We compared the HapMap samples with more conventionally-ascertained samples used in population-and forensic-genetic studies, including the HGDP-CEPH panel, making use of published genome-wide autosomal SNP data and Y-STR haplotypes, as well as producing new Y-STR data. We found that the HapMap samples were representative of their broad geographical regions of ancestry according to all tests applied. The YRI and JPT were indistinguishable from independent samples of Yoruba and Japanese in all ways investigated. However, both the CHB and the CEU were distinguishable from all other HGDP-CEPH populations with autosomal markers, and both showed Y-STR similarities to unusually large numbers of populations, perhaps reflecting their admixed origins. Conclusions/Significance: The CHB and JPT are readily distinguished from one another with both autosomal and Ychromosomal markers, and results obtained after combining them into a single sample should be interpreted with caution. The CEU are better described as being of Western European ancestry than of Northern European ancestry as often reported. Both the CHB and CEU show subtle but detectable signs of admixture. Thus the YRI and JPT samples are well-suited to standard population-genetic studies, but the CHB and CEU less so.

On montre, sur des exemples, comment trois méthodes d’analyse des données provenant d’essais multilocaux, dérivées en particulier des travaux de MANDEL (1971), BURDON (1979), GOFFINET & VINCOURT (1980), permettent d’enrichir la connaissance des sélectionneurs. Les effets des génotypes sont regardés comme fixés ou comme aléatoires. Ces techniques, qui permettent d’établir une continuité entre les concepts utilisés en sélection (héritabilité) et les critères empiriques de choix, peuvent être diffusées auprès des sélectionneurs au travers des programmes HENDER et MULTILOC (développés en FORTRAN sur Mini-6, CII-HB)., From the approaches of MANDEL (1971), BURDON (1979), and GOFFINET & VINCOURT (1980), three methods of analysis of genotype x environment data are presented through experimental results. Estimations obtained for genotype performance, with fixed or random effects, seemed to be able to improve the value of selection criteria, by integrating in the same approach both empirical practice and the concepts that are commonly used in selection, such as heritability or predicted gain.

From the approaches of MANDEL (1971), BURDON (1979), and GOFFINET & VINCOURT (1980), three methods of analysis of genotype x environment data are presented through experimental results. Estimations obtained for genotype performance, with fixed or random effects, seemed to be able to improve the value of selection criteria, by integrating in the same approach both empirical practice and the concepts that are commonly used in selection, such as heritability or predicted gain.; On montre, sur des exemples, comment trois méthodes d’analyse des données provenant d’essais multilocaux, dérivées en particulier des travaux de MANDEL (1971), BURDON (1979), GOFFINET & VINCOURT (1980), permettent d’enrichir la connaissance des sélectionneurs. Les effets des génotypes sont regardés comme fixés ou comme aléatoires. Ces techniques, qui permettent d’établir une continuité entre les concepts utilisés en sélection (héritabilité) et les critères empiriques de choix, peuvent être diffusées auprès des sélectionneurs au travers des programmes HENDER et MULTILOC (développés en FORTRAN sur Mini-6, CII-HB).