Table 271Proposed Number of Hox Genes in Various Extant and Extinct

question 60

Multiple Choice

Table 27.1.Proposed Number of Hox Genes in Various Extant and Extinct Animals
-All things being equal,which of these is the simplest 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 Table 27.1?

• A)the occurrence of seven independent duplications of individual Hox genes
• B)the occurrence of 14 independent duplications of individual Hox genes
• C)the occurrence of two distinct duplications of the entire seven-gene cluster,followed by the loss of one cluster
• D)the occurrence of a single duplication of the entire seven-gene cluster

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Definitions:

Ruff Degradation

A chemical reaction used for the oxidation of aldoses to smaller aldoses.

NaBH4

Sodium borohydride, a reducing agent commonly used in the reduction of ketones and aldehydes to alcohols.

HNO3

Nitric acid, a highly corrosive and toxic strong acid used in the manufacture of fertilizers and explosives.

D-Tagatose

A ketohexose sugar related to fructose that has potential health benefits and is used as a low-calorie sweetener.