Best of all, markers are universal. Well, to understand how to use this test wisely and effectively, a basic understanding of genetics and some of the terminology is essential. One version is usually dominant, another recessive. Each trait will have two alleles for the same characteristic. So, two alleles can produce three genotypes.
Markers also have alleles.
They are genetically normal. They will not carry any marker genes for the prcd mutation because the mutation isn t present. When an animal carries one or two copies of the recessive allele for the disease they also carry the markers associated with the disease. The PRA found is some other breeds is caused by a different gene than prcd , for example, the rcd1 gene in Irish Setters. The gene for prcd -PRA is very old, as is the chromosome it now calls home.