The Hox genes came to regulate each of the following in what sequence, from earliest to most recent?
1)identity and position of paired appendages in protostome embryos
2)anterior-posterior orientation of segments in protostome embryos
3)positioning of tentacles in cnidarians
4)anterior-posterior orientation in vertebrate embryos
A) 4 → 1 → 3 → 2
B) 4 → 2 → 3 → 1
C) 4 → 2 → 1 → 3
D) 3 → 2 → 1 → 4
E) 3 → 4 → 1 → 2

Question

Quizplus · Accepted Answer

The Hox genes first regulated the positioning of tentacles in cnidarians, an early and fundamental role in the development of body plans. They then evolved to determine the anterior-posterior orientation of segments in protostome embryos, followed by specifying the identity and position of paired appendages in these embryos. Finally, they took on the role of determining the anterior-posterior orientation in vertebrate embryos, reflecting their expanding role in the development of increasingly complex organisms.

The Hox Genes Came to Regulate Each of the Following