You have identified a mutation in a gene that seems to decrease transcription of another gene 2000 bp away from the mutation site. what regulatory sequence, which may be found within another gene, has likely been mutated in this instance? a. homeodomain motif. b. enhancer sequence. c. proximal elements. d. upstream activator. e. sequence core promoter.

Enhancer sequence.

Explanation:

Enhancers may be defined as the transcription factors that are used to enhance or increase the activity of the gene. Enhancers bind with the transcription factors to regulate and increase its expression.

The mutation in the enhancers decrease the transcription of  of the other gene. These sequences lies far away from the transcription site but still known to increase the rate of transcription. Hence, the mutation has been done in the enhancer sequences.

Thus, the correct answer is option (b).