Proposed Number of Hox Genes in Various Extant and Extinct

question 38

Multiple Choice

Proposed Number of Hox Genes in Various Extant and Extinct Animals
$$\begin{array} { | c | c | c | c | } \hline \begin{array} { c } \text { Last } \\\text { Common } \\\text { Ancestor } \\\text { af Bilateria }\end{array} & \begin{array} { c } \text { Last Common } \\\text { Ancestor of Insects } \\\text { and Vertebrates }\end{array} & \begin{array} { c } \text { Ancestral } \\\text { Vertebrates }\end{array} & \text { Mammals } \\\hline 4 & 7 & 14 & 3840 \\\hline\end{array}$$
What conclusion can best be drawn from the data in the table?

• A) Land animals have more Hox genes than do those that live in water.
• B) All bilaterian phyla have had the same degree of expansion in their numbers of Hox genes.
• C) The expansion in number of Hox genes throughout vertebrate evolution cannot be explained merely by three duplications of the ancestral vertebrate Hox cluster.
• D) Extant insects all have seven Hox genes.

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