Genetic polymorphism of eserine resistant esterases in canine plasma

Six plasma eserine resistant esterase phenotypes were observed in a population of 1438 dogs consisting of 38 breeds. Analysis of parentage records of the dogs examined revealed that the phenotypic variation of eserine resistant esterases was controlled by 3 codominant alleles ESA, ESB and ESC at one autosomal locus. The gene frequency of ESB was high in most of the breeds examined. Allele ESC was only seen in 5 Japanese native breeds, Akita, Shikoku, Hokkaido, Shinshu-Shiba and Mino-Shiba, and in a Spitz dog. Allele ESA has a low frequency in Japanese breeds but a higher frequency in some of the European breeds tested.