Data from: Association mapping of morphological traits in wild and captive zebra finches: reliable within but not between populations

Identifying causal genetic variants underlying heritable phenotypic variation is a longstanding goal in evolutionary genetics. We previously identified several quantitative trait loci (QTL) for five morphological traits in a captive population of zebra finches (Taeniopygia guttata) by whole-genome linkage mapping. We here follow up on these studies with the aim to narrow down on the quantitative trait variants (QTN) in one wild and three captive populations. First, we performed an association study using 672 single nucleotide polymorphisms (SNPs) within candidate genes located in the previously identified QTL regions in a sample of 939 wild-caught zebra finches. Then, we validated the most promising SNP-phenotype associations (n = 25 SNPs) in 5,228 birds from four populations. Genotype-phenotype associations were generally weak in the wild population, where linkage disequilibrium (LD) spans only short genomic distances. In contrast, in captive populations, where LD blocks are large, apparent SNP-effects on morphological traits (i.e. associations) were highly repeatable with independent data from the same population. Most of those SNPs also showed significant associations with the same trait in other captive populations, but the direction and magnitude of these effects varied among populations. This suggests that the tested SNPs are not the causal QTN but rather physically linked to them, and that LD between SNPs and causal variants differs between populations due to founder effects. While the identification of QTN remains challenging in non-model organisms, we illustrate that it is indeed possible to confirm the location and magnitude of QTL in a population with stable linkage between markers and causal variants.

Usage Notes

data_phenotypes_BodyMassBody mass data used for the initial linkage analysis. A detailed description of the file is in the README.data_phenotypes_TarsusDigitRatioTarsus length, body size and digit ratio data used for the initial linkage analysis. A detailed description of the file is in the README.data_phenotypes_TarsusBodySizeDigitRatio.txtdata_genotypes_SequenomGenotypic data for all individuals from the wild and multiple captive populations used for the validation study. A detailed description of the file is in the README.data_snp_annotationAdditional information for all SNPs used for the validation study. A detailed description of the file is in the README.