Abstract
Sera from 7 dog families comprising 20 parents with 48 offspring and 70 unrelated dogs of various breeds have been studied with regard to polymorphism of esterases. Isoelectric focusing in Polyacrylamide gels of pH ranges 4.2–4.9 and 4–6 revealed great variation of phenotypes. These appeared as complex band patterns always with more than 8 zones. Treatment with an organophosphorous compound and ions of heavy metals strongly indicate that the majority of zones represent arylesterase (ArE) whereas some of the bands are Cholinesterase. ArE phenotypes in families together with the appearances of band patterns in the 70 unrelated dogs are in agreement with a genetic theory of 1 locus with 5 codominant alleles. These have temporarily been named ArE(D), ArE(H), ArE(K), ArE(Q) and ArE(W) with ArED being the most anodal phenotype and the others in logical order. The ArE(K) and ArE(Q) were most common but phenotypes representing the ArE(D), ArE(H) and ArE(W) alleles were each observed in several animals.