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Hadi Esfandyari

Post doc

Hadi Esfandyari


PhD Student:
EGS-ABG Doctoral Candidate Agreement Between Aarhus University and Wageningen University, Holland and Graduate School of Science and Technology, Aarhus University

PhD project:
Strategies for using genetic interactions in genomic breeding programs for coress-bred performance

Anders Christian Sørensen, Senior Scientist, PhD, Department of Molecular Biology and Genetics, Aarhus University
Piter Bijma, Dr., Department of Animal Sciences, Wageningen University, Holland

01.09.2011 - 31.08.2015

The aim of this project is to assess the possibilities of using genetic interaction parameters in the selection of animals to use in cross breeding programs. The project will make use of stochastic simulations and theoretical predictions to evaluate the underlying mechanisms that influence the outcome of using genomic prediction of interaction terms.


Cross breeding programs are used intensively in the production of pigs and poultry. It is also gaining interest in beef and dairy cattle breeding. The basis for the advantage of cross breeding programs over pure breeding programs is the existence of interactions between alleles (dominance) and between genes (epistasis) and a difference in allele frequencies between breeds. Genetic improvement of the pure breeds has not been fully expressed in the cross-bred production animals, and the existence of epistatic interactions is thought to be one of the reasons for this. Genomic selection is a novel procedure to select animals based on DNA-information. This procedure is currently under implementation in several breeding organizations across speciess. However, all implementations are only considering additive genetic effects, which by definition do not contribute to cross-bred superiority.
Considring non-additive effects requires more sophisticated models when optimizing selection decisions, whether in pure-bred or cross-bred applications, since an animal's genetic value as a breeding invividual depends on the potential mates.
Selection for heterosis tends to cause divergence in allele frequencies between breeds, whereas selection within the pure lines for similar breeding goals tends to cause convergence in allele frequencies. It is important to find the balance between these two opposing factors, and that balance likely depends on the time horizon of the breeding program. 

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