Polymorphism of feline beta-globins studied by reversed-phase high-performance liquid chromatography.

OBJECTIVE

To characterize the feline beta-globin system with respect to the number and genetics of adult beta-globin chains.

ANIMALS

84 domestic and purebred cats (9 breeds), 14 cats were mildly to severely anemic. For genetic analyses, 12 litters with 1 to 5 offspring for a total of 29 kittens.

PROCEDURE

Feline globins from erythrocyte lysates were separated by reversed-phase high-performance liquid chromatography and analyzed on the basis of retention time and area of each beta-globin peak. Mixing studies with half the amount of hemoglobin (Hb) from 2 cats were performed to assign the beta-globin peaks in each cat. The Hb from 60 cats were also separated by standard isoelectric focusing methods.

RESULTS

Heme and alpha- and beta-globins were effectively separated by high-performance liquid chromatography. Although there was only 1 alpha-globin, a total of 6 beta-globins (I through VI) were identified, with each cat having 1 to 4 beta-globin chains. From analysis of the number of beta-globins, their relative amounts, and Hb mixing studies, 17 beta-globin patterns were observed. The beta-globin pattern in healthy and anemic cats was identical. Family studies documented an autosomal codominant mode of inheritance of the adult beta-globins and a linkage of 2 beta-chains forming haplotypes.

CONCLUSIONS

Biochemical and genetic evidence for the greatest polymorphism of adult beta-globins thus far described in any species is provided. A feline beta-globin gene region with 2 linked beta-globin gene loci and 2 and 5 alleles is proposed.

CLINICAL RELEVANCE

Better understanding of feline Hb will likely be helpful for diagnosis of hemoglobinopathies in anemic cats.