A third allele in the horse albumin system

Starch gel electrophoresis according to Gahne (1966) reveals three new phenotypes designated FI, I and IS in horse serum albumin. Family material comprising 97 sire families with a total number of 2742 foals and their dams and population material comprising 2867 adult horses representative of the Swedish Trotter breed were examined. The results were consistent with a genetic theory of three codominant, autosomal alleles F, I and S controlling the six albumin phenotypes observed. The gene frequencies were estimated to be 0.489, 0.049 and 0.462, respectively, for the F, I and S genes in the Swedish Trotter breed. The risk of making false exclusions in paternity controls in the albumin system, if the I allele is not considered, is discussed.