The shared genetic mechanisms in limb development between vertebrates and insects illustrate the principle of evolutionary conservation. Which statement correctly describes the role of specific genes and proteins in the development of limbs in both vertebrates and insects?
1
Sonic hedgehog and Hedgehog proteins are responsible for determining the proximal-distal axis in both vertebrates and insect limbs.
2
Engrailed and Apterous proteins specify the dorsal-ventral axis in vertebrate limbs, whereas their homologues specify the same axis in insect limbs.
3
Radical fringe protein, crucial in vertebrate limb development by forming the apical ectodermal ridge, plays a similar role in insect limb development through the same interaction with fibroblast growth factors.
4
The anterior-posterior axis in both vertebrate and insect limbs is similarly regulated by Hedgehog proteins, and the dorsal-ventral axis is specified by the expression of engrailed in both phyla.