Statistical models and methods for genomic evaluations of quantitative traits
Genomic markers (e.g. single nucleotide polymorphisms; SNP) can be used to assess genetic variation in a population and to study heritable influences on health or performance traits. There are biological dependencies between SNP markers caused by linkage and linkage disequilibrium between chromosome segments and influenced by population structure. Typical family structures in livestock are half-sibling (e.g. dairy cattle) or full-sibling families (e.g. chicken). We determine the dependency between SNP pairs by estimating recombination rate and linkage disequilibrium using SNP genotypes. This additional information is then taken into account in the genome-based evaluation of quantitative traits, for example by grouping genomic markers according to their interdependence. Furthermore, from the frequency of recombination events, we derive genetic maps which are a useful tool for optimising breeding strategies. With the routinely collected data from performance testing and the genotypic information suitable breeding animals (“top sires”) can then be identified.