| Abstract: | Understanding the genetic basis of traits involved in adaptation is a majorchallenge in evolutionary biology but remains poorly understood. Here, we usegenome-wide association mapping using a custom 50 k single nucleotidepolymorphism (SNP) array in a natural population of collared flycatchers toexamine the genetic basis of clutch size, an important life-history trait inmany animal species. We found evidence for an association on chromosome 18 whereone SNP significant at the genome-wide level explained 3.9% of thephenotypic variance. We also detected two suggestive quantitative trait loci(QTLs) on chromosomes 9 and 26. Fitness differences among genotypes weregenerally weak and not significant, although there was some indication of asex-by-genotype interaction for lifetime reproductive success at the suggestiveQTL on chromosome 26. This implies that sexual antagonism may play a role inmaintaining genetic variation at this QTL. Our findings provide candidateregions for a classic avian life-history trait that will be useful for futurestudies examining the molecular and cellular function of, as well asevolutionary mechanisms operating at, these loci. |
