8.15: Genomic selection
- Tessa Jacobs
- Kor Oldenbroek
From the example of the EBV of the young bull it became clear that the accuracy of his EBV will remain low until there are phenotypic observations on the daughters of the young bull. That takes a lot of time. It would be very interesting if there is a way to increase the accuracy of the EBV already at younger age, without having to wait for daughters to be born. It would also be very interesting if there is a way to estimate breeding values for traits that are difficult or expensive to measure, such as some health related traits or meat quality, without having to infect animals, or make detailed x-rays, or slaughter them. And since a few years there is a method that can do just that: genomic selection.
Schematic overview of the logistics behind genomic selection. The reference population provides the information to estimate associations between phenotype and SNP genotypes. These associations are then translated into prediction equations that are used to estimate genomic breeding values for animals without phenotype but with SNP genotypes outside the reference population.
The concept behind genomic selection is explained in chapter 4.15.3. With genomic selection it is possible to estimate an animal’s breeding value quite accurately without the need for own performance or performance of large number of offspring. Genomic selection is based on estimation of detailed associations between a very dense set of genetic markers (SNP) and phenotypes on a select group of animals. These associations can then be used to predict the so-called genomic breeding values (gEBV) for related animals that have been genotyped for a large set of SNP, but that do not have ‘traditional’ information for accurate EBV’s like own performance or a large number of offspring with phenotypes. With genomic selection the DNA of the animal thus provides information for estimating the breeding value, without having to collect phenotypes on the animal itself or on its close relatives.