Question

the melanocortin - 1 - receptor (mc1r) gene helps determine the coat color phenotype in rock pocket mice.
a researcher collected dna from individual rock pocket mice and used dna sequencing to identify the order of nucleotides in the mc1r gene for each mouse. a subset of the sequencing data, which shows the results for two mice, is shown in figure 1.
mouse 1:
dna sequencing graph for mouse 1 with nucleotides c t c c a c c c g c a c at positions 45 - 56
position: 45 46 47 48 49 50 51 52 53 54 55 56
mouse 2:
dna sequencing graph for mouse 2 with nucleotides c t c c a c c t g c a c at positions 45 - 56
position: 45 46 47 48 49 50 51 52 53 54 55 56
figure 1: dna sequencing data for positions 45 - 56 of the mc1r gene in two rock pocket mice.
which of the following can be determined from the data in figure 1?
choose 1 answer:
a mouse 2 is a transgenic organism, while mouse 1 is not.
b mouse 1 and mouse 2 differ in at least one nucleotide of the mc1r gene.
c mouse 2 has a longer coat than mouse 1 does.
d mouse 1 produces a functional mc1r protein, while mouse 2 does not.

Explanation:

• Option A: Transgenic organisms have foreign DNA inserted, but the data only shows Mc1r gene sequences, not foreign DNA. So A is incorrect.
• Option B: By comparing the nucleotide sequences (Mouse 1: C T C C A C C C G C A C; Mouse 2: C T C C A C C T G C A C), position 52 has C in Mouse 1 and T in Mouse 2. So they differ in at least one nucleotide.
• Option C: The data is about DNA sequences of the Mc1r gene, not coat length. So C is incorrect.
• Option D: The data shows gene sequences, not protein functionality. So D is incorrect.

Answer:

B. Mouse 1 and Mouse 2 differ in at least one nucleotide of the Mc1r gene.