A genetic change that caused a certain Hox gene to be expressed along the tip of a vertebrate limb bud instead of farther back helped make possible the evolution of the tetrapod limb. This type of change is illustrative of

Question

Quizplus · Accepted Answer

The genetic change that caused the Hox gene to be expressed along the tip of a vertebrate limb bud is an example of a change in a developmental gene or its regulation that altered the spatial organization of body parts. This change ultimately resulted in the evolution of the tetrapod limb.

Answer: D
 The term "heterochrony" describes a change in the timing or rate of developmental events, which can also result in altered spatial organization of body parts. However, this answer choice does not specifically address the genetic change related to the Hox gene that is mentioned in the question stem.

Answer options A, B, and E are incorrect because they do not accurately reflect the specific change described in the question stem. Choice A refers to an environmental influence on development, which is not relevant to this scenario. Choice B refers to retaining juvenile traits into adulthood, which is also not applicable in this context. Choice E refers to the process of gene duplication, which is not directly related to the Hox gene expression change outlined in the question.

A Genetic Change That Caused a Certain Hox Gene to Be