Dr. Stevens is examining the DNA sequences of a group of mice. He notices that in one of the mice, one nucleotide has been substituted with another in the part of the DNA sequence that codes for fur color. However, despite the substitution, the mouse still has the same fur color as the other mice that have the typical DNA sequence.

Question

Dr. Stevens is examining the DNA sequences of a group of mice. He notices that in one of the mice, one nucleotide has been substituted with another in the part of the DNA sequence that codes for fur color. However, despite the substitution, the mouse still has the same fur color as the other mice that have the typical DNA sequence.

What best explains why the nucleotide substitution in the mouse does not change its phenotype?
A.
DNA sequences do not determine the color of a mouse's fur.
B.
The mouse has a completely different DNA sequence than the other mice.
C.
Substitutions in the nucleotides in the DNA of the mouse can affect its genotype but rarely affect its phenotype.
D.
The substituted nucleotide produces codons that correspond to the same amino acid that is found in the other mice.

Answer 1

D. The substituted nucleotide produces codons that correspond to the same amino acid that is found in the other mice. This means that the change in the DNA sequence did not result in a change in the protein produced, and therefore did not affect the mouse's phenotype in terms of fur color.