Question

Marfan syndrome is the result of inheriting a single allele. Individuals with Marfan syndrome are tall and long-limbed, and have both cardiovascular and eye defects. Of what type of inheritance is the phenotype of Marfan syndrome an example?

A) incomplete dominance
B) pleiotropy
C) codominance
D) a recessive disorder
E) gene linkage

Answer 1

Pleiotropy

Step-by-step explanation:

Pleiotropy is a genetic situation in which a single gene influences or controls the expression of several phenotypes. Consequently, any change that happens to pleiotropic genes always affect multiple characters on the respective organisms.

From the information available, it is obvious that the gene for Marfan syndrome affects the limb, the cardiovascular system and the eye of subjects. Hence, Marfan syndrome gene is a pleiotropic gene.

The correct option is B.

Answer 2

Pleiotropy

Step-by-step explanation:

Marfan syndrome has several signs and symptoms depending on the individual affected.

The main manifestations of the disease are related to the skeletal system, in which the affected individual presents with elongated limbs, elevated height, scoliosis and thoracic deformations; the cardiac system, characterized by mitral valve prolapse (closing of the upper and lower chambers of the left side of the heart) and dilation of the aorta; and the ocular system, characterized by a detachment in the lens of the eye, and myopia.

The ability of genetic defects such as Marfan syndrome to reach such distinct organs is called pleiotropy.