Question

Based on the pedigree shown below, how is it possible for the daughter to have green eyes while the rest of the family has brown eyes?
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A
The mother must be homogeneous and the father must be heterogeneous.
B
Both parents must be homogeneous.
C
Both parents must be heterogeneous.
D
The father must be homogeneous and the mother must be heterogeneous.

Answer 1

C

Brown is dominant to green. The daughter must be homozygous recessive (bb), so each brown parent must carry a recessive allele (Bb). Two Bb parents can produce a bb child (Punnett square: 1/4 bb).