Genes could be studied in two ways to resolve the relationship between the annelids and the arthropods. First, the sequences of these genes could be compared among these and other animals just like the sequences of any genes to show how they are related. Further, the expression of Hox genes involved in segmentation could be studied— it may be that, if these two groups belong in different clades, the expression of Hox genes has evolved convergently to give them the similar segmentation which scientists have long noticed.
Work Step by Step
Review Ch. 21 and other earlier material in the book to see how gene sequence data helps us to decipher how organisms are related. Further, these parts of the text show the role of the Hox genes is setting up body structure. Also find and review the idea of analogy/convergent evolution.