Question

student wants to determine how likely an autosomal dominant trait (X/x) is to be passed on. A father does not have the trait (x), but the mother does (Xx).
What will the Punnett square look like?
50% Xx; 50% xx.
50% XX; 50% Xx
• 25% Xx; 75% xx.
• 75% Xx; 25% XX

Answer 1

Mother (Xx) gametes: X, x
Father (xx) gametes: x, x

Punnett square:
x x
X | Xx Xx
x | xx xx

Genotype proportions: 50% Xx, 50% xx.
Phenotype: 50% show the dominant trait (Xx), 50% do not (xx).