In addition to excessive bleeding, persons with hemophilia may have excessive bruising, pain and swelling in the joints, vision loss, anemia, or neurological problems. This is a result of the effects of a single gene loss and is called
A) codominance.
B) multiple allelism.
C) pleiotropy.
D) environmental effects.

Question

Quizplus · Accepted Answer

The effects of a single gene loss manifesting in multiple symptoms or traits in different body systems is referred to as pleiotropy. This is seen in hemophilia, where the loss of a single gene that codes for a blood clotting factor leads to excessive bleeding, bruising, joint pain and swelling, anemia, vision loss, and neurological problems. Codominance refers to the expression of two different alleles of a gene equally (e.g. black and white stripes on a zebra), multiple allelism refers to the presence of more than two alleles of a gene in a population (e.g. human blood types), and environmental effects refer to the impact of external factors on phenotypic expression (e.g. the effect of nutrition on height).

In Addition to Excessive Bleeding, Persons with Hemophilia May Have