In negative regulation, a. the gene is never transcribed. b. the gene is always transcribed. c. the binding of an activator stimulates transcription. d. transcription can be turned off when a repressor binds to the dna near the promoter. e. a transcription factor is required in order for the gene to be transcribed.

Part a - which gene to compare? in this exercise, you will use the cytochrome c oxidase i (coi) gene to investigate relationships among salmon species. (this gene encodes a protein that functions in the mitochondrial electron transport chain.) you will compare the coi gene sequences from your salmon test samples to the standard sequences for each salmon species. in order for the coi gene to be useful for distinguishing among the different salmon species, which three statements must be true?