Co-option of the limb patterning program in cephalopod eye development

BMC Biology

Kyle J. McCulloch¹  Francesca R. Napoli¹  Christina M. Daly¹  Stephanie Neal¹  James H. Coleman¹  Kristen M. Koenig¹ 

[1] John Harvard Distinguished Science Fellowship Program, Harvard University, 02138, Cambridge, MA, USA;Department of Organismic and Evolutionary Biology, Harvard University, 02138, Cambridge, MA, USA;

关键词: Eye;    Cephalopod;    Eye evolution, Lens;    Vision;    Spiralia;    Wnt;    Limb patterning;    Dlx;   

DOI  :  10.1186/s12915-021-01182-2

来源: Springer

【 摘 要 】

BackgroundAcross the Metazoa, similar genetic programs are found in the development of analogous, independently evolved, morphological features. The functional significance of this reuse and the underlying mechanisms of co-option remain unclear. Cephalopods have evolved a highly acute visual system with a cup-shaped retina and a novel refractive lens in the anterior, important for a number of sophisticated behaviors including predation, mating, and camouflage. Almost nothing is known about the molecular-genetics of lens development in the cephalopod.ResultsHere we identify the co-option of the canonical bilaterian limb patterning program during cephalopod lens development, a functionally unrelated structure. We show radial expression of transcription factors SP6-9/sp1, Dlx/dll, Pbx/exd, Meis/hth, and a Prdl homolog in the squid Doryteuthis pealeii, similar to expression required in Drosophila limb development. We assess the role of Wnt signaling in the cephalopod lens, a positive regulator in the developing Drosophila limb, and find the regulatory relationship reversed, with ectopic Wnt signaling leading to lens loss.ConclusionThis regulatory divergence suggests that duplication of SP6-9 in cephalopods may mediate the co-option of the limb patterning program. Thus, our study suggests that this program could perform a more universal developmental function in radial patterning and highlights how canonical genetic programs are repurposed in novel structures.

【 授权许可】

CC BY