Question

cystic fibrosis affects the lungs, the pancreas, the digestive system, and other organs, resulting in symptoms ranging from breathing difficulties to recurrent infections. which of the following terms best describes this expression of phenotypes?

incomplete dominance

multiple alleles

pleiotropy

epistasis

Explanation:

Pleiotropy is when one gene affects multiple phenotypic traits. Cystic fibrosis (caused by a single gene mutation) affects multiple organs (lungs, pancreas, digestive system etc.) and causes multiple symptoms (breathing difficulties, recurrent infections etc.), which fits the definition of pleiotropy. Incomplete dominance is about blending of traits (e.g., red and white flower parents giving pink - flowered offspring). Multiple alleles refer to a gene having more than two allelic forms (e.g., ABO blood group system). Epistasis is when one gene masks the expression of another gene.

Answer:

pleiotropy