Feline adult β-globin polymorphism reflected in restriction fragment length patterns

Abstract

Adult domestic cats (Felis catus) appear to have the most polymorphic β-globin system of any species. Reversed-phase high-performance liquid chromatography (RP-HPLC) revealed one α-chain and six different β-globin chains. Each cat may have one to four different β-globins, and a total of 17 different β-globin patterns were identified. Based on family studies, a β- globin gene region with two linked β-globin gene loci and two to five alleles was proposed. In order to further define the molecular basis of this polymorphism we performed Southern blot analysis of the β-globin gene region from 25 cats with 13 different HPLC patterns. Genomic DNA was digested with five restriction endonucleases (BamHI, Bg/II, EcoRI, HindIII, and PstI) and blots were hybridized with a human β-globin probe. Restriction fragment length polymorphisms (RFLPs) with one to five fragments of 2.2-23 kb in size were found with Bg/II, EcoRI, HindIII, and Pst/l. Cats with specific HPLC β- globin patterns had a unique DNA restriction pattern. The similarly sized BamHI and HindIII fragments of 4.6 kb suggest the presence of two closely linked genes. Furthermore, family studies suggest an autosomal codominant mode of inheritance of the β-globin chains with seven haplotypes. Thus the RFLP data analyzed in the context of the HPLC haplotypes provide evidence at the DNA level for a feline β-globin gene region with two closely linked gene loci and two to five alleles.