Data from: Genomic dissection of variation in clutch size and egg mass in a wild great tit (Parus major) population

Clutch size and egg mass are life history traits that have been extensively studied in wild bird populations, as life history theory predicts a negative trade-off between them, either at the phenotypic or genetic level. Here, we analyse the genomic architecture of these heritable traits in a wild great tit (Parus major) population, using three marker-based approaches - chromosome partitioning, quantitative trait locus (QTL) mapping and a genome-wide association study (GWAS). The variance explained by each great tit chromosome scales with predicted chromosome size, no location in the genome contains genome-wide significant QTL, and no individual SNPs are associated with a large proportion of phenotypic variation, all of which may suggest that variation in both traits is due to many loci of small effect, located across the genome. There is no evidence that any regions of the genome contribute significantly to both traits, which combined with a small, non-significant, negative genetic covariance between the traits, suggests the absence of genetic constraints on the independent evolution of these traits. Our findings support the hypothesis that variation in life history traits in natural populations is likely to be determined by many loci of small effect spread throughout the genome, which are subject to continued input of variation by mutation and migration, although we cannot exclude the possibility of an additional input of major effect genes influencing either trait.2497_indiv_5591_markersThe 2497_indiv_5591_markers.map file is a file of marker names and positions, slightly amended from the plink format with column headings: chromosome, marker_name, marker_order, genetic_distance_(cM). For more information see the ReadMe.txt file.2497_indiv_5591_markersThe .ped file is a file of genotypes in plink style (see http://pngu.mgh.harvard.edu/~purcell/plink/). The column headings are: Family ID, Individual ID, Paternal ID, Maternal ID, Sex (1=male; 2=female; other=unknown), Phenotype (followed by the genotypes). For more information see the ReadMe.txt file2497_indiv_phenotype2497_indiv_phenotype.txt file. This file contains the phenotypes used in the analysis. Note that phenotypes are not available for all genotyped individuals. For more information please see the ReadMe.txt fil