Question

Poliosis can be caused by a germ-line mutation or a somatic mutation. What evidence would best support that the individual's poliosis is caused by a germ-line mutation?

A.
The affected individual was born with poliosis.

B.
The affected individual developed poliosis later in life.

C.
The affected individual has a family history of poliosis.

D.
The affected individual had no family history of poliosis.

Answer 1

C. A family history of poliosis best supports a germ-line mutation, because germ-line mutations are heritable and appear in multiple family members. A somatic mutation would typically be limited to the individual (no family history) and can arise later or as a mosaic even if present at birth.