Achondroplasia is an inherited condition in humans that results in a form of short-limbed dwarfism.
This condition is controlled by a single gene with two alleles. The dominant allele (DDD) codes for achondroplasia and the recessive allele (ddd) codes for average height.
Two parents who both have achondroplasia have a child of average height.
Use a genetic diagram to show:
State the probability that a second child born to these parents will be of average height.
Achondroplasia is caused by a dominant allele. Explain what is meant by the term dominant allele.
Suggest why the percentage of people with achondroplasia in the population remains low, even though it is a dominant trait.
