A theoretical protein, blue2, is coded for by the blu2 gene. This protein codes for a blue pigment used by the organism to protect it from damaging UV rays from sunlight. The enzyme alterase binding to the blu2 operator halts transcription of blue2. A blu2 operator mutation causes a conformational change that does not allow alterase to bind to operator.

The question is:

What may be observed as a result of the described mutation in an individual?

1) Skin cancer due to UV rays

2) Darker blue pigmentation

3) A lack of alterase for other functions it may serve

4) The release of a different pigment color

The correct answer is B.

In this theoretical molecular cascade, we have three key parts, the blue2 gene, the blue2 operator and the enzyme alterase.

The enzyme alterase stops the expression of the blue2 gene by binding to its operator, and therefore the blue pigment protein.

The blue2 operator has a specific binding spot for alterase. If this binding spot is changed due to a conformational change, the alterase would not be able to bind to the operator and the blue2 gene could express undisturbedly, resulting in increased concentration of the blue pigment protein.