Principles of Genetics and Breeding

4.2.5 Sex influenced genes

Two types of inheritance exhibit sexually related effects, although neither is sex linked. Sex-influenced genes show differing patterns of expression in each sex-usually, the trait behaves as dominant in one sex and as a recessive in the other. Sex-influenced genes occur only on Autosomes. For e.g., baldness in man is found to be inherited as sex-influenced trait. The gene B for baldness is found to be dominant in males and recessive in females. In heterozygous conditions it expresses itself only in male sex. The inheritance of gene B for baldness and gene b for non-bladness in man and woman can be tabulated as follows: