Student performance on clicker question asked at the end of the small-group
activity.
Clicker question 1 (This questions targets LO1): The breast cancer 1 (BRCA1) gene has
been implicated in breast and ovarian cancer.
Below is a pedigree of a family showing the incidence of breast cancer with a particular
BRCA1- allele. BRCA1+/BRCA1- females who have this particular allele of BRCA1have a high chance of developing early onset breast cancer.
There are no BRCA1-/BRCA1- individuals in this family.
BRCA1- mutations usually cause breast cancer in females but not in males; one member
in generation I is heterozygous for the mutant allele; individuals II-1 and II-5 are
BRCA1+/BRCA1+.
Which mode of inheritance is most consistent with the information in the pedigree?
A. Autosomal dominant
B. Autosomal recessive
C. X-linked dominant
D. X-linked recessive
E. More than one of the above is possible
Answer: A, 87% correct
Clicker question 2 (This questions targets LO2): If a man has a BRCA1 mutation
(remember BRCA1-/BRCA1- individuals do not exist), what is the chance he will pass
the mutation on to his son?
A. 100%
B. 75%
C. 50%
D. 25%
E. 0%
Answer: C, 100% correct
Clicker question 3: A woman is BRCA1+/BRCA1-. If you could analyze 10 of her noncancerous somatic cells, you expect to find that each cell will have:
A. Two BRCA1+ copies
B. One BRCA1+ copy and one BRCA1- copy
C. Two BRCA1- copies
Answer: B, 87% correct
Clicker question 4: The BRCA1- allele is:
A. Dominant acting at the cellular and organismal levels
B. Recessive acting at the cellular and organismal levels
C. Dominant acting at the cellular level and recessive acting at the organismal level
D. Recessive acting at the cellular level and dominant acting at the organismal level
Answer: D, 81% correct