Question

girl of normal stature is born to two parents with achondroplasia who have very short stature, especially disproportionately short arms and legs. What is the probability (by Punnett Square analysis) that any pregnancy this girl eventually has will result in the birth of an infant with achondroplasia if her partner also has normal stature?A. Three out of four (75%)B. Two out of four (50%)C. One out of four (25%)D. Zero out of four (0%)

Answer 1

Answer:

Option D, Zero out of four (0%)

Explanation:

As we know,  achondroplasia is an autosomal dominant pattern. Now a girl having normal stature mate with a partner who also has a normal stature.

Thus let us assume -

Allele for disproportionately short arms and legs be represented by "A"

while allele for normal stature be represented by "a"

Now genotype of parents would be

Female - aa

Male - aa

Thus,

aa x aa

aa, aa, aa, aa

Thus, option D is  correct.