little is known about the developmental mechanisms underlying cephalopod limb evolution
cephalopod limbs evolved by parallel activation of a genetic program for appendage development that was present in the bilaterian common ancestor.
Despite striking differences in form and function, all limbs develop in embryos using similar fundamental processes, like producing an outgrowth from the body and placing structures such as fingers, feathers, or suckers at appropriate positions.
The extent of the genetic similarities between cuttlefish, mammals and insects suggests that this mechanism is likely to provide instructions about where cells position themselves in the developing limb. The next step is to examine how these common systems are interpreted differently to give arms, legs, wings and other limb forms.
an ancient and conserved developmental genetic program facilitated the origin of cephalopod limbs
fine-scale regulatory changes may have played a role in the diversification of cephalopod limb morphologies.
homologous developmental mechanisms underlie the multiple parallel origins of limbs in bilaterians.
Common Design 