Question

The evidence from Panganiban et al's studies that appendage-like outgrowths of the body wall are homologous in all bilaterally symmetric animals is particularly strong because

A. it supports morphological evidence that the limbs of arthropods and tetrapods are structurally homologous.
B. the same pattern of Dll expression was found in a wide range of distantly related taxa.
C. variation in Dll expression leads to differences in the branching patterns of arthropod limbs.
D. Dll has the same gene sequence in all taxa analyzed.

Answer 1

The strength of the evidence lies in the conserved pattern of Dll gene expression across a variety of taxa, supporting the homology of appendage-like structures in bilaterally symmetric animals and the evolutionary link between appendages of different species.

Step-by-step explanation:

The evidence from Panganiban and colleagues' research is particularly strong that appendage-like outgrowths of the body wall are homologous in all bilaterally symmetric animals because it revealed that the same pattern of Dll (Distal-less) gene expression was found across a wide range of distantly related taxa. This finding underpins the concept of deep homology, where genetic mechanisms underlying the development of these appendages are conserved from a common ancestor. The presence of a shared Dll expression pattern in the development of appendages across different species provides strong molecular evidence for the morphological similarities observed in the appendages of arthropods and tetrapods, suggesting evolutionary relationships that supplement and support this hypothesis.