The following question refers to this hypothetical situation.
A female fly, full of fertilized eggs, is swept by high winds to an island far out to sea. She is the first fly to arrive on this island and the only fly to arrive in this way. Thousands of years later, her numerous offspring occupy the island, but none of them resembles her. There are, instead, several species, each of which eats only a certain type of food. None of the species can fly, and their balancing organs (halteres) are now used in courtship displays. The male members of each species bear modified halteres that are unique in appearance to their species. Females bear vestigial halteres. The ranges of all of the daughter species overlap.
In each fly species, the entire body segment that gave rise to the original flight wings is missing. The mutation(s) that led to the flightless condition could have ________.
A) duplicated all of the Hox genes in these flies' genomes
B) resulted in paedomorphosis
C) altered the expression of a Hox gene
D) originated in another species

Question

Quizplus · Accepted Answer

Altering the expression of a Hox gene could lead to changes in the development of body segments, potentially leading to the loss of the body segment that gave rise to the flight wings. This is a possible mechanism for the evolution of flightlessness in these fly species. Option A, duplicating all of the Hox genes, would not necessarily lead to the loss of a body segment. Option B, paedomorphosis, refers to the retention of juvenile features in mature individuals and is not a likely explanation for the loss of a body segment. Option D, originating in another species, does not provide a clear explanation for the specific genetic mechanism underlying the loss of a body segment.

The Following Question Refers to This Hypothetical Situation