Genetic associations of fitness-relevant trait variations in birds, using a genomic approach of heterozygosity-fitness analysis
Zusammenfassung der Projektergebnisse
Understanding the mechanisms underlying adaptive genetic variation in natural populations is a central aim in evolutionary biology. We have analysed the relationship between genetic diversity measured as heterozygosity and reproductive traits and survival in a wild blue tit population over a study period of 9 years. At first, we developed 106 genetic markers distributed across the whole song bird genome, and classified these markers as presumably functional or neutral. We then tested the heterozygosity of these two sets of markers for their association with fitness-related traits, such as clutch size, sired eggs, recruitment to the breeding area and early survival. The observed positive relationships between neutral markers and reproductive traits indicated inbreeding depression effects. Indeed, we documented the occurrence of some consanguineous matings by pedigree analysis and found evidence for a cryptic genetic population structure that can promote the occurrence of inbreeding events in the population. Genome-wide inbreeding effects were further indicated by heterozygosity correlations among the neutral loci. If we accounted for different inbreeding levels by a full-sibling approach, we detected negative relationships between the set of functional markers and early survival traits. Single loci effects, however, were weak and inconsistent among the sexes and traits. This finding could be attributed to the local impact of many functional loci with weak effects. Our comprehensive study has shown that different sets of genetic markers (functional and neutral) and different study designs (random population and fullsibling approach) have different power to detect local or general genomic effects of heterozygosity-fitness relationships in wild populations.
Projektbezogene Publikationen (Auswahl)
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2010. Avian genome evolution: insights from a linkage map of the blue tit (Cyanistes caeruleus). Heredity 104, 67-78
Hansson B, Ljungqvist M, Dawson DA, Mueller JC, Olano-Marin J, Ellegren H, Nilsson J-A
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2010. Genome-wide set of 106 microsatellite markers for the blue tit (Cyanistes caeruleus). Molecular Ecology Resources 10, 516-532
Olano-Marin J, Dawson DA, Girg A, Hansson B, Ljungqvist M, Kempenaers B, Mueller JC
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2011. Linking genetic mechanisms of heterozygosity-fitness correlations to footprints of selection at single loci. Evol Ecol 25, 1-11
Mueller JC, Hermisson J, Olano-Marin J, Hansson B, Kempenaers B
