Question

You have identified a mutation in a gene that deletes that gene's promoter. Without knowing anything else about the gene in question, how would you classify the allele produced by this mutation?

A) this is likely to be a dominant allele
B) this is likely to be a haplosufficient allele
C) this is likely to be a gain of function allele
D) this is likely to be a loss of function allele
E) both A and C are correct

Answer 1

Without knowing anything else about the gene in question, a mutation that deletes a gene's promoter would likely result in a loss of function allele, which is typically considered recessive. Option d.

Step-by-step explanation:

If a mutation in a gene deletes the gene's promoter, it is likely to result in an allele that does not express the gene product because the promoter region is critical for initiating transcription. Therefore, the allele produced by this mutation would typically be classified as loss of function, which generally suggests a recessive behavior, unless the function lost contributes to a dominant negative effect. However, without additional context such as the effect of the protein product in a multimeric complex or if it is related to a developmental pathway that can lead to gain-of-function effects by the loss, we would assume it is simply a loss of function. In this context, the correct answer would be D) this is likely to be a loss of function allele.