Genomic selection in the Australian sheep industry

Many livestock industries around the world have invested heavily in research and development of genomic selection since it was first proposed by Meuwissen et al. in 2001. The basic idea is that if genomic tests with large numbers of markers are available, they can be used to genotype a "reference" population of animals which are also measured for a wide range of economically important traits. Marker effects on these traits can be estimated, establishing a genomic prediction which can then be applied to industry animals outside the reference population. In other words, once genomic prediction equations are developed from an appropriate resource flock, industry animals can be genotyped and a genomic prediction of their genetic merit can be made without the need to measure them. This use of genomic information allows more accurate selection at an earlier age and for traits which are hard to measure, therefore increasing selection response primarily by shortening generation interval. The first livestock species to capitalise on genomic selection in a significant way has been the dairy industry. In the past dairy sire selection has relied on expensive and lengthy progeny testing programs, with sires not achieving high accuracy estimated breeding values until their daughters have recorded lactations. Genomic predictions are now available on young bulls virtually from birth which are approaching the accuracies of progeny test breeding values (around 75%). With an appropriately designed breeding program to capitalise on this information it is possible to double current rates of genetic gain (Pryce and Daetwyler, 2011).