Question

Sol.(c) [Key Concept: Polygenic Inheritance — Skin Colour] Skin colour in humans is the classic example of polygenic inheritance — controlled by multiple gene pairs (estimated 3-6 loci) that act additively, producing a continuous spectrum of phenotypes. Each gene contributes incremental melanin pigment. AABB = darkest; aabb = lightest; intermediate genotypes give intermediate shades. Flower colour in Mirabilis jalapa is an example of incomplete dominance (single gene); pod shape in pea is controlled by a single gene; production of male honey bees is parthenogenesis.