RT Journal Article
SR Electronic
T1 Evolution of limb development in cephalopod mollusks
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 379735
DO 10.1101/379735
A1 Oscar A. Tarazona
A1 Davys H. Lopez
A1 Leslie A. Slota
A1 Martin J. Cohn
YR 2019
UL http://biorxiv.org/content/early/2019/05/18/379735.abstract
AB Cephalopod mollusks evolved numerous anatomical novelties, including arms and tentacles, but little is known about the developmental mechanisms underlying cephalopod limb evolution. Here we show that all three axes of cuttlefish limbs are patterned by the same signaling networks that act in vertebrates and arthropods, although they evolved limbs independently. In cuttlefish limb buds, Hedgehog is expressed anteriorly. Posterior transplantation of Hedgehog-expressing cells induced mirror-image limb duplications. Bmp and Wnt signals, which establish dorsoventral polarity in vertebrate and arthropod limbs, are similarly polarized in cuttlefish. Inhibition of Bmp2/4 dorsally caused ectopic expression of Notum, which marks the ventral sucker field, and ectopic sucker development. Cuttlefish also show proximodistal regionalization of Hth, Exd, Dll, Dac, Sp8/9, and Wnt expression, which delineates arm and tentacle sucker fields. These results suggest that cephalopod limbs evolved by parallel activation of a genetic program for appendage development that was present in the bilaterian common ancestor.