Final answer:
A mutation in the region of a steroid hormone receptor that binds to DNA is most likely to affect the gene expression.
Step-by-step explanation:
A mutation in the region of a steroid hormone receptor that binds to DNA is most likely to affect the gene expression. Steroid hormone receptors are proteins that bind to specific DNA sequences and regulate the transcription of target genes. If there is a mutation in the DNA binding region of the receptor, it may no longer be able to bind to its target DNA sequence effectively. This can result in dysregulated gene expression, leading to various physiological changes or disorders.