Which of the following situations most likely describes a recessive genetic disorder?
A) The mutant allele of the gene encodes a completely nonfunctional protein.
B) The mutant allele of the gene encodes a protein that has both the normal function and a new, harmful function.
C) The mutant allele of the gene encodes a protein that has a new, harmful function.
D) The mutant allele of the gene encodes a protein with the normal function but twice the normal activity.

Question

Quizplus · Accepted Answer

In a recessive genetic disorder, an individual must inherit two copies of the mutant allele (one from each parent) to express the disorder phenotype. If the mutant allele encodes a completely nonfunctional protein, the individual will only express the disorder phenotype if they inherit two copies of the mutant allele. This is characteristic of a recessive genetic disorder. Choices B, C, and D describe situations where the mutant allele may have dominant properties, meaning that the individual only needs to inherit one copy of the mutant allele to express the disorder phenotype.

Which of the Following Situations Most Likely Describes a Recessive