Question

(i) State Mendel's law of dominance.
(ii) Suppose you are given two pairs of contrasting characters: Seed colour → yellow and green, Seed coat → round and wrinkled.

Selfing among hybrids of F1	RY	Ry	rY	ry
RY
Ry
rY
ry
F2 generation

Answer 1

(i) Mendel's Law of Dominance says that characters are controlled by discrete units called factors, which occur in pairs, with one member of the pair dominating the other in a dissimilar pair. This law explains the expression of only one of the parental characters in the F₁ generation and the expression of both in the F₂ generation.

(ii)

Selfing among hybrids of F1	RY	Ry	rY	ry
RY	RRYY Round yellow	RRYy Round yellow	RrYY Round yellow	RrYy Round yellow
Ry	RRYy Round yellow	RRyy Round green	RrYy Round yellow	Rryy Round green
rY	RrYY Round yellow	RrYy Round yellow	rrYY Wrinkled yellow	rrYy Wrinkled yellow
ry	RrYy Round yellow	Rryy Round green	rrYy Wrinkled yellow	rryy Wrinkled green
F2 generation	Round yellow = 9/16	Round green = 3/16	Wrinkled yellow = 3/16	Wrinkled green = 1/16