Question

A woman heterozygous for polydactyly (extra fingers and toes), a dominant trait, is married to a normal man. What is the probability of producing an offspring that has extra fingers or toes?

Answer 1

Answer:

The correct answer is -50%

Explanation:

Polydactyly is a dominant trait where a person gets an extra finger or toes the dominant allele is represented by P = allele for polydactyly, and the recessive allele represented by p = normal allele

So, the heterozygous woman will be - Pp & the normal man will be - pp.  The presence of one allele of polydactyly will be able to show its effect as it is dominant.

Cross between heterozygous woman & normal man:

Gametes:

   P                              p

p Pp (Show polydactyly) pp (Normal phenotype)

p Pp (Show polydactyly) pp (Normal phenotype)

From the above Punnett square, the probability of an offspring that has extra fingers or toes will be 1/2 or 50%.