Evolution has provided enormous diversity in the number of vertebrae among vertebrate species. Vertebrae are differentiated during embryonic development by
A)hormone induction.
B)the length of the backbone.
C)the degree of structural support needed.
D)the pattern of homeotic gene expression.

Question

Quizplus · Accepted Answer

The differentiation of vertebrae is controlled by the pattern of homeotic gene expression during embryonic development. Homeotic genes are master regulatory genes that control the developmental fate of body segments in animals. Different patterns of homeotic gene expression can lead to differences in the number, shape, and structure of vertebral segments. Therefore, the best choice is D - the pattern of homeotic gene expression.

Evolution Has Provided Enormous Diversity in the Number of Vertebrae