Evolutionary Developmental Biology (Evo-Devo)
Visual systems, like any trait, are the result of coordinated spatial and temporal patterns of gene regulation and expression throughout development. These essential gene regulatory networks are repeatedly found in similar traits across animals, suggesting homology of the trait, however functional links between development and mature cell types are missing in most animal lineages.
Projects in the lab focus on addressing the functional link between regulation of the genome and photoreceptor cell type differentiation through next-gen sequencing, knockouts, transgenic reporters, and measures of gene expression. We also focus on characterizing mature cell types physiologically, and connecting these to animal behavior.
By comparing developmental programs within and between species, we can better understand the evolution of visual systems.
See our latest research in Google Scholar:
Nematostella vectensis has 29 opsins across 3 clades of the animal opsin tree. Anthozoan-specific opsins (ASO) I and II are only found in anthozoans like corals and sea anemones. Cnidopsins are found in all cnidarians and group with the Xenopsins, a spiralian-specific group that was lost in Ecdysozoa and deuterostomes. ASO-II (purple) is particularly intriguing because corals and anemones have expanded this group greatly, it is not present in medusozoans, and it is the sister clade to c-opsins, the vertebrate visual receptors.
McCulloch KJ, Babonis LS, Liu A, Daly CM, Martindale MQ, Koenig KM. Nematostella vectensis exemplifies the exceptional expansion and diversity of opsins in the eyeless Hexacorallia. Evodevo. 2023 Sep 21;14(1):14. doi: 10.1186/s13227-023-00218-8.
Nematostella larval swimming behavior is light- and wavelength-dependent. In UV and violet light, larvae swim into the water column, entering the planktonic state. At 425 nm, there is a behavioral switch causing larvae to seek the substrate at blue and green wavelengths. This behavior is not phototactic. It is likely in the shallow estuaries where N. vectensis lives, short wavelength UV light indicates very shallow water which could be itself damaging to the animal or be a signal of potential drying out in very shallow tidal waters.
Lilly, E., Muscala, M., Sharkey, C. R., & McCulloch, K. J. (2024). Larval swimming in the sea anemone Nematostella vectensis is sensitive to a broad light spectrum and exhibits a wavelength-dependent behavioral switch. Ecology and Evolution, 14, e11222. https://doi.org/10.1002/ece3.11222
380 nm – larvae swimming in water column
525 nm – larvae swim toward substrate