Question

The sheep breeding program wants to produce white-wool lambs (recessive trait) from two heterozygous gray-wool parents (Gg × Gg). Using probability principles, what is the chance that any individual lamb will have white wool?
Question 6 options:

25% chance, because only the gg genotype produces white wool phenotype

100% chance, because both parents carry the recessive white wool allele

75% chance, because gray wool is the dominant trait in this cross

50% chance, because each parent contributes one allele to each offspring

Answer 1

Correct answer: 25% chance.

Explanation: For Gg × Gg, the Punnett square gives genotypes GG, Gg, Gg, gg — so 1 out of 4 (25%) is gg. Equivalently, each parent contributes the g allele with probability 1/2, so the chance both do is 1/2 × 1/2 = 1/4. Only gg shows the recessive white-wool phenotype.