Answer to Question #57566 in Genetics for Sanjukta Ghosh

Question

What is an example of incomplete dominance with gain-of-funtion allele?

Thank you.

Answer 1

Answer: achondroplasia

Explanation:
Gain-of-function mutation: A mutation that confers new or enhanced activity on a protein. The most common mechanism by which a mutant allele is dominant is through a gain-of-function mutation. In one type от gain-of-function mutation, termed hypermorphic, the protein is produced in excessive quantities or is somehow hyperactive. The presence of a single normal allele can do nothing to tone down the activity resulting from the mutant allele. This situation is observed, for example, in an extreme type of dwarfism called achondroplasia and in many human cancers.

Achondroplasia is the most common form of dwarfism. It actually shows Incomplete Dominance.
If you are heterozygous for the trait, you will be a dwarf. If you are homozygous for the trait, it is embryonic lethal.