Your friend works in a lab that is studying why a particular mutant strain of Drosophila grows an eye on its wing.Your friend discovers that this mutant strain of Drosophila is expressing a transcription factor incorrectly.In the mutant Drosophila, this transcription factor, which is normally expressed in the primordial eye tissue, is now misexpressed in the primordial wing tissue, thus turning on transcription of the set of genes required to produce an eye in the wing primordial tissue.If this hypothesis is true, which of the following types of genetic change would most likely lead to this situation?

Question

Quizplus · Accepted Answer

A mutation within the upstream enhancer of the gene is most likely to result in incorrect expression of the transcription factor in a different tissue than normal. Enhancers are short DNA sequences that regulate the transcription of nearby genes by interacting with specific transcription factors. Mutations in the enhancer region can alter the binding sites for transcription factors, leading to changes in gene expression. In this case, a mutation in the enhancer near the transcription factor gene could allow it to be expressed in the wrong tissue, causing the formation of an eye on the wing. Mutations in the transcription factor gene itself are less likely to result in this specific phenotype, as they would likely affect expression in all tissues where the transcription factor is normally found. Mutations in the TATA box, a DNA sequence that helps to start transcription, could also affect gene expression but are less likely to shift expression to a completely different tissue.

Your Friend Works in a Lab That Is Studying Why