Abstract: | Understanding the genetic basis of traits involved in adaptation is a major
challenge in evolutionary biology but remains poorly understood. Here, we use
genome-wide association mapping using a custom 50 k single nucleotide
polymorphism (SNP) array in a natural population of collared flycatchers to
examine the genetic basis of clutch size, an important life-history trait in
many animal species. We found evidence for an association on chromosome 18 where
one SNP significant at the genome-wide level explained 3.9% of the
phenotypic variance. We also detected two suggestive quantitative trait loci
(QTLs) on chromosomes 9 and 26. Fitness differences among genotypes were
generally weak and not significant, although there was some indication of a
sex-by-genotype interaction for lifetime reproductive success at the suggestive
QTL on chromosome 26. This implies that sexual antagonism may play a role in
maintaining genetic variation at this QTL. Our findings provide candidate
regions for a classic avian life-history trait that will be useful for future
studies examining the molecular and cellular function of, as well as
evolutionary mechanisms operating at, these loci. |