Multiple structural genes for the alpha chain of canine (Canis familiaris) hemoglobin

There are two forms of the alpha chain of canine hemoglobin differing only at residue 130. One form (taualpha) contains threonine at this position, the other (Aalpha) contains alanine. Studies of two Labrador dog families strongly support the existance of multiple alpha-chain structural genes as the basis of the alpha-chain heterogeneity. There must be at least one gene locus for Talpha and one for Aalpha; the exact number of loci has not been determined. Two other dog breeds, the Basenji and the Beagle, also have both Talpha and Aalpha chains.