Table 32.1. Proposed Number of Hox Genes in Various Extant and Extinct Animals

-All things being equal, which of these is the most parsimonious explanation for the change in number of Hox genes from the last common ancestor of insects and vertebrates to ancestral vertebrates, as shown in Table 32.1?
A)The occurrence of 7 independent duplications of individual Hox genes.
B)The occurrence of 2 distinct duplications of the entire 7-gene cluster, followed by the loss of one cluster.
C)The occurrence of a single duplication of the entire 7-gene cluster.

Question

Table 32.1. Proposed Number of Hox Genes in Various Extant and Extinct Animals
 
-All things being equal, which of these is the most parsimonious explanation for the change in number of Hox genes from the last common ancestor of insects and vertebrates to ancestral vertebrates, as shown in Table 32.1?
A)The occurrence of 7 independent duplications of individual Hox genes. 
B)The occurrence of 2 distinct duplications of the entire 7-gene cluster, followed by the loss of one cluster. 
C)The occurrence of a single duplication of the entire 7-gene cluster.

Quizplus · Accepted Answer

A single duplication of the entire 7-gene cluster is the most parsimonious explanation because it requires the fewest number of evolutionary events. Options A and B both require multiple duplications and/or losses, which are less parsimonious.

Table 321 Proposed Number of Hox Genes in Various Extant and and Extinct