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bioRxiv · 10.1101/2021.04.22.441006

Co-option of the Limb Patterning Program in Cephalopod Lens Development

Neal, S.·McCulloch, K. J.·Napoli, F.·Daly, C. M.·Coleman, J. H.·Koenig, K. M.
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Abstract

Across 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. Here we identify the co-option of the canonical bilaterian limb pattering program redeployed 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 limb, and find the regulatory relationship reversed, with ectopic Wnt signaling leading to lens loss. This regulatory divergence suggests that duplication of SP6-9 in cephalopods may mediate this co-option. These results suggest that the limb network does not exclusively pattern appendage outgrowth but is performing a more universal developmental function: radial patterning.

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Neal, S., McCulloch, K. J., Napoli, F., Daly, C. M., Coleman, J. H., Koenig, K. M.. 2021-04-23. Co-option of the Limb Patterning Program in Cephalopod Lens Development. https://doi.org/10.1101/2021.04.22.441006

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