Haemoglobin polymorphism in Nigerian breeds of sheep and goats

Abstract

This study described the genetic structure of Nigerian breeds of sheep and goats at haemoglobin (Hb) locus level. Animals used for the study comprised 100 each of Red Sokoto and West African Dwarf (WAD) goats, and 400 sheep comprising 100 per breed of Balami, Yankasa, Uda and WAD with 50 animals per sex within breed. Five milliliters of blood was obtained from each animal by jugular venipuncture and dispensed into sample bottles containing Ethylene Diamine Tetra Acetic Acid and analyzed using cellulose acetate paper electrophoresis. Genotypic frequencies were then estimated. Goats showed Hb AA, AB and BB genotypic frequencies of 0.485, 0.430 and 0.085, respectively while sheep had only the Hb AA genotype. Red Sokoto goats had Hb AA, AB, BB frequencies of 0.490, 0.430 and 0.080, respectively while the WAD goats had corresponding values of 0.480, 0.430 and 0.090. Genotypic frequencies were similar in both sexes of sheep and goats indicating that there was no effect of sex on Hb frequency. It is concluded that Hb polymorphism in goats is defined by the expression of three genotypes (2 homozygotes, Hb AA, Hb BB, and 1 heterozygote Hb AB), while in sheep there was no polymorphism at the Hb locus; only the Hb AA was exhibited.

Keywords: Sheep, goats, Nigeria, Haemoglobin, genotype frequency, gene frequency