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 the number of Hox genes from the last common ancestor of insects and vertebrates to ancestral vertebrates, as shown in the table?
A) The occurrence of seven independent duplications of individual Hox genes.
B) The occurrence of two distinct duplications of the entire seven-gene cluster, followed by the loss of one cluster.
C) The occurrence of a single duplication of the entire seven-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 the number of Hox genes from the last common ancestor of insects and vertebrates to ancestral vertebrates, as shown in the table?
A) The occurrence of seven independent duplications of individual Hox genes. 
B) The occurrence of two distinct duplications of the entire seven-gene cluster, followed by the loss of one cluster. 
C) The occurrence of a single duplication of the entire seven-gene cluster.

Quizplus · Accepted Answer

The most parsimonious explanation, meaning the simplest explanation that accounts for all the facts, is the occurrence of a single duplication of the entire seven-gene cluster. This would double the number of Hox genes from the ancestral state without requiring multiple independent events.

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