Choose the term below that best describes why the phenotypic ratio of the gene w
ID: 138219 • Letter: C
Question
Choose the term below that best describes why the phenotypic ratio of the gene would differ from standard Mendelian Inheritance:
Clopidogrel resistance is a condition that describes how the drug Clopidogrel (Plavix) behaves in individual people. Clopidogrel resistance is determined by alleles of the CYP2C19 gene, which encodes an enzyme that metabolizes the drug. People who are homozygous for the wild-type allele are normal metabolizers for the drug, and therefore it is effective in preventing coronary artery disease. People who have two copies of a mutant allele of the gene are poor metabolizers of clopidogrel. Therefore the drug is not effective in these people and they can have dangerous reactions to the drug. People that are heterozygous have one wild-type allele and one mutant allele, and are considered intermediate metabolizers.
Select one:
a. Lethal Alleles
b. Multiple Alleles
c. Incomplete Dominance
d. Epistasis
e. Pleiotropy
Explanation / Answer
Answer: Pleiotropy occurs when one gene influences two or more seemingly unrelated phenotypic traits, phenotypic ratio of the gene would differ from standard Mendelian Inheritance.
For example, phenylketonuria is a disease caused by pleiotropy. Sickle cell anemia is also a disease caused by pleiotropy.