Figure 32.4

-Dll is a gene known to direct limb development in the fruit fly.Researchers studying this gene have found that it is also expressed in developing appendages in animals from many other phyla as well,supporting the hypothesis that all animal appendages may be homologous.However,suppose researchers looking at Dll activity had instead found the results shown in Figure 32.4.What would these results suggest?
A)Dll is not actually involved in appendage development.
B)Appendages evolved separately in protostomes and deuterostomes.
C)Appendages coevolved with segmentation.
D)All animal appendages are homologous.

Question

Figure 32.4
 
-Dll is a gene known to direct limb development in the fruit fly.Researchers studying this gene have found that it is also expressed in developing appendages in animals from many other phyla as well,supporting the hypothesis that all animal appendages may be homologous.However,suppose researchers looking at Dll activity had instead found the results shown in Figure 32.4.What would these results suggest?
A)Dll is not actually involved in appendage development. 
B)Appendages evolved separately in protostomes and deuterostomes. 
C)Appendages coevolved with segmentation. 
D)All animal appendages are homologous.

Quizplus · Accepted Answer

The figure shows that Dll is expressed in the developing appendages of a sea urchin, which is a deuterostome. This suggests that the role of Dll in limb development may have evolved separately in protostomes and deuterostomes, rather than being a shared ancestral trait.

Figure 32.4 -Dll Is a Gene Known to Direct Limb Development in Direct