Question

The normal sequence of genes along a hypothetical chromosome is ABC*DEFGH, where letters represent genes and the asterisk (*) represents the centromere. A mutation event results in a chromosome in which the sequence of genes is ABC*DGFEH. This type of mutation is

A) a nonsense mutation.
B) an inversion.
C) a translocation.
D) a duplication.
E) a point mutation.

Answer 1

The mutation resulting in the chromosome sequence ABC*DGFEH is an inversion, where a chromosome segment flips and reattaches, altering the gene order without adding or losing genetic material.

Step-by-step explanation:

The chromosome mutation described by the student results in a chromosome with the sequence ABC*DGFEH, where the gene order has been rearranged but no genetic material has been gained or lost. This is indicative of an inversion, where a section of a chromosome breaks off, rotates 180 degrees, and then reattaches.

Since the genes D, G, F, and E have been inverted compared to the original sequence ABC*DEFGH, option B) an inversion is the correct answer. Other types of chromosomal mutations include deletions, duplications, and translocations, but they do not match the given scenario. An inversion specifically alters the orientation of a segment within its chromosome without changing the overall genetic content.