Question

Achondroplasia is a form of dwarfism caused by a dominant allele. the homozygous dominant genotype causes death, so individuals who have this condition are all heterozygotes. if a person with achondroplasia mates with a person who does not have achondroplasia, what percentage of their children would be expected to have achondroplasia?

Answer 1

The percentage of people that will have achondroplasia would be 50 % or 1/2. This is because by simply performing a punnet square for this mono hybrid cross. We can see that it would be a cross between :

Aa X aa

This would result in 50 % of the offspring to display the genotype of aa and the remaining 50 % to display Aa.