Mice that are homozygous for a complete deletion of the wild-type gene "T" develop multiple tumors in a variety of tissues very early in life.Gene "T" is most likely:
A)an activated oncogene.
B)a dominant tumor suppressor gene.
C)an oncogene.
D)a proto-oncogene.
E)a tumor suppressor gene.

Question

Quizplus · Accepted Answer

Homozygous deletion of a wild-type tumor suppressor gene can lead to development of multiple tumors in various tissues. This suggests that gene "T" is a tumor suppressor gene, and loss of its function (due to homozygous deletion) promotes tumorigenesis. Note that options A, C, and D refer to oncogenes and proto-oncogenes, which are genes that promote cell proliferation and can promote tumorigenesis when mutated or overexpressed. Option B refers to a dominant tumor suppressor gene, which is a rare type of tumor suppressor gene that requires only one functional copy to prevent tumorigenesis.

Mice That Are Homozygous for a Complete Deletion of the Wild-Type