Crossbreeding is abundant in the livestock industry and relies on within-line genetic selection of purebred breeding animals that are mated between lines to produce crossbred production animals. The advantage of using crossbred compared to purebred production animals is that they outperform their purebred parents due to a phenomenon known as heterosis.
Capitalizing on heterosis, the ultimate goal of pig and poultry breeding programs, is to improve performance of crossbred animals. Crossbreeding is also increasingly more important for cattle breeding, given the observed increased use of crossbred production animals. At present, selection is mainly based on performance measured on purebred animals, in highly controlled environments. For many traits, however, the genetic correlation between purebred and crossbred performance is considerably lower than one. In addition, heterosis, which is the result of dominance and epistatic effects, is not captured in purebred performance. This indicates that selection based on purebred performance ignores part of the genetic variation, leading to suboptimal selection responses in crossbred performance.
Therefore, the overall objective of this project is to improve accuracy of prediction of phenotypes of crossbred animals by utilizing the total genetic variance. These predictions will rely on both purebred and crossbred performance, measured on animals that may be closely or distantly related to the breeding animals, but typically will not be their offspring. The developed knowledge includes prediction of selection response when using both crossbred and purebred phenotypic performance, and designs of breeding programs that efficiently and accurately generate required genomic breeding values. The developed tools will enable implementation of genomic breeding value estimation for crossbred performance in practice.
The project consists of the following three key objectives:
- Investigate optimal breeding program designs that use both purebred and crossbred information, to enable accurate estimation of additive and non-additive genetic effects
- Development of parametric models to quantify contributions of additive and dominance effects to breeding values for crossbred performance
- Development of non-parametric models to quantify the total genetic effects underlying crossbred performance, including additive, dominance and epistatic effects
The GenoMiX project is a collaboration between the Animal Breeding and Genomics Centre of Wageningen University and Radboud University. The project is funded by Breed4Food and STW.