Sheep Hb
by Joe Wayne Templeton
Category: Genetic polymorphisms

Five breeds of sheep (Columbia, Targhee, Rambouillet, Lincoln, and Suffolk) were found to possess two hemoglobin types (Hb. A and Hb. B) when their hemoglobins were examined by disc gel electrophoresis. The hemoglobin alleles proved to be co-dominant. Three of the breeds (Columbia, Targhee, and Rambouillet) were maintained at altitudes of 4,800 to 7,500 feet above sea level and the Lincoln breed investigated was maintained at altitudes of 750 to 1,200 feet above sea level. These four breeds had a frequency of Hb. A of 16% or greater. The Suffolk flock maintained at an altitude of 250 feet above sea level had a frequency of Hb. A of approximately 5%. These data suggest an adaptive advantage for Hb. A at higher altitudes. An increase in inbreeding was observed to be associated with an increase in the homozygosity at the hemoglobin locus. The association was linear to a level of 35% inbreeding after which there was a noticeable drop in the amount of homozygosity as inbreeding exceeded 35%. There were no significant differences among the means of production traits for the three classes of hemoglobin alleles when the mean values of the following production traits were tested: (1) average daily gain from birth to weaning, (2) weaning weight, (3) weaning conformation, (4) weaning condition, (5) weaning index, (6) yearling weight, (7) average daily gain from weaning to yearling, (8) yearling condition, (9) yearling conformation, (10) yearling grease fleece weight, (11) yearling fleece grade, and (12) yearling index.