Final answer:
The answer to the question is B, which is the movement of a transposable element within the genome or between genomes. This movement, facilitated by the enzyme transposase, is the defining feature of transposition.
Step-by-step explanation:
Transposition and Its Outcomes
The question asks which of the following always results from transposition: A. Creation of a mutant phenotype, B. Movement of a transposable element within the genome or between genomes, C. Increase in the number of copies of a transposable element, D. The gene for transposase being turned off after being expressed, E. More than one of the above. The correct answer is B. Movement of a transposable element within the genome or between genomes. Transposition refers to the process by which transposons, or “jumping genes,” move from one part of the genome to another. This can have various effects, including altering gene expression, which might lead to a mutant phenotype or disrupting the function of genes.
However, the key defining feature of transposition is the movement itself, which can be ensured by the action of the enzyme transposase that is encoded by the transposons. While this movement can lead to an increased number of transposable elements if a replicative mechanism is involved, it does not always happen, and therefore C is not always accurate. Similarly, the creation of a mutant phenotype and silencing of the transposase gene after expression are possible but not guaranteed consequences.