Question

The nonmutant allele of the BRCA1 gene helps to suppress tumor formation in women who are heterozygous for the mutation. Women heterozygous for BRCA1 nevertheless have a 50% to 70% chance of developing breast cancer before age 70, and the usual reason is that the nonmutant allele is lost or inactivated in a lineage of cells. One possible mechanism for such "loss of heterozygosity" is:

A. germ cells in the affected individual develop a mutation in the nonmutant allele of BRCAL.
B. a somatic mutation in a breast cell inactivates the nonmutant BRCA1 allele.
C. a silent mutation occurs in the nonmutant BRCA1 allele.

Answer 1

Option B

Step-by-step explanation:

A silent mutation has no effect on the gene activity and function hence option C is incorrect. Germ cells would affect the gametes produced, not the body's proteins hence the answer would be B.