Genomic selection: What are the perspectives for poultry industries?

Abstract

Genomic selection is based on an evaluation of the genetic values of the candidates for selection through a «molecular score» calculated from their genotypes for a great number of DNA markers. A first step consists in estimating the effects of the markers on a reference population that has been genotyped and phenotyped for the traits that need improving. The establishment of this table of genotypic values allows for the calculation of the genetic values of the candidates in the subsequent generations, for which genotyping might then prove sufficient. This strategy was implemented in dairy cattle in just a few years. The operators in charge of selection in the other animal production sectors have witnessed this change and hence legitimately regard this approach as useful input for them. The existence of a 600k SNP chip for the chicken now allows for the application of genomic selection in layers and broilers. Tools for high-throughput genotyping in other poultry species are being developed. There are three components of genetic progress that can be improved, regardless of the species. First, selection intensity can be increased for traits non-measurable in routine (product quality, feed efficiency, resistance to diseases). Then, the accuracy of genetic values can be improved, especially for males whenever traits are expressed by females only. Finally, the generation interval can be reduced through early evaluation of candidates (egg production). What is more, genomic evaluation provides, for the first time, the opportunity to select pure-bred individuals from the selection nucleus for their usefulness in crossbreeding and production. The implementation costs of genomic selection are quite high. This is due to the size of the reference population needed for accurate evaluation, the huge number of genotyping operations to be carried out on candidates and the great diversity of populations to be selected. However, use of large numbers of breeding animals in the poultry industry could help counterbalance these costs.