Question

Some mice have inherited a genetic mutation that causes them to have a band of white fur around the middle of their bodies. What is most likely true about an ancestor of these mice?
A.
A change in its DNA resulted in a modified protein that controls fur color.
B.
A change in its fur color modified the structure of its DNA.
C.
A change in its environment changed the DNA of only part of its body.
D.
A change in its food source affected only the fur around its stomach.

Answer 1

A. A change in its DNA resulted in a modified protein that controls fur color.

Reason: The trait is inherited, so a germline mutation in a pigment-related gene (altering the protein it encodes) is the most likely cause. The other options describe reverse causation or somatic/environmental effects that wouldn’t produce an inheritable banded coat.