Inheritance of skin folding (wrinkling) of sheep

Abstract

The Mendelian technique for investigating methods of inheritance was employed to discover the mechanism which controlled skin folding in sheep. Experimental matings were designed to use, for P₁ and P₂, Border Leicester and wrinkled Merino sheep. These were considered possibly homozygous or nearly so for plain body and wrinkling and had the opposed characteristics of no skin folding and a high degree of it respectively. The matings progressively gave rise to F₁, F₂, and F₃ generations. Subsequently a backcross was made by mating F₁ and P₂. The investigation discloses that skin folding, or wrinkling, and the absence of skin folding, or plain body, are paired genetically as the two extremes of a range of characterization in which the ultimate types may be homozygous. Within this multifactor situation genes responsible for plain body are possibly associated with epistatic effects. The situation gives rise to a series of heterozygous intermediates from which samples with particular gene frequencies may be withdrawn as breeds of sheep with defined characterization. Estimates of the heritability of either plain body or wrinkling within the samples will vary according to the particular gene frequency for which any estimate is made.