Erythrocyte potassium and haemoglobin type polymorphisms in fleeceweight-selected and control Romney sheep

摘要

Erythrocyte potassium (K) and haemoglobin (Hb) type polymorphisms were examined in ram and ewe hoggets and mature ewes from the Massey University fleeceweight-selected and control lines of Romney sheep. There was no difference in the frequency of low potassium (LK) v. high potassium (HK) phenotypes between the lines, and no difference in greasy hogget fleeceweight between the phenotypes. Erythrocyte K+concentration was positively related to fleeceweight in HK hoggets but no relationship existed in LK hoggets. The frequency of Hb types differed significantly between the selection lines, the frequency of Type BB being greater in the fleeceweight-selected than control lines. Hogget fleeceweights were significantly lowerin Type BB animals than in Type AA or AB animals. It is concluded that selection for greasy fleeceweight in these lines has not altered the frequency ofK types but has been associated with an increase in the frequency of the Hb Type B allele. However, this difference has most likely arisen as a consequence of genetic drift rather than as a correlated response to selection for fleeceweight.