6.9: Realised additive relationship
In practice, the additive genetic relationships can be estimated using pedigree, or using genomic information. If genomic information is used (for example SNP markers), you can imagine that the more markers are genotyped per animal, the more accurate you can estimate how much of the genome two animals have in common. This is called the realised additive genetic relationship. In the future, when complete genome sequences are available for the animals, the exact additive genetic relationship can be determined. At this moment this is not the case yet because of financial limitations. In practical animal breeding the additive genetic relationship in most cases is estimated using pedigree relationships. In some cases, like with of genomic selection, the animals are genotyped for a large number of genetic markers, which allows for the more accurate estimate of the additive genetic relationship using the genomic information.