9 December 2025

Uncovering the evolution of Mediterranean soft corals with genomics

By Didier Aurelle, Université de Toulon, CNRS

The yellow gorgonian (Eunicella cavolini) is one of the most widespread octocoral species found in the Mediterranean sea. As with other Anthozoans (the groups of cnidarians including hard corals, black corals, sea anemons and gorgonians), it is an ecosystem engineer, contributing to the habitats of various species. Eunicella cavolini is listed as Near Threatened in the IUCN Red List of Threatened Species and is impacted among others by climate change and fishing activities. In the area of Marseille this species is present at different depths and near pollution sources.

Eunicella cavolini is listed as Near Threatened by the IUCN Red List. Photo by  F. Zuberer.

Research has shown that there is a possibility of hybridisation between E. cavolini and E. singularis. As E. singularis hosts symbiotic algae (Symbiodiniaceae), this hybridisation questions the evolution of symbiosis. This makes the yellow gorgonian a fascinating model species to study genomic evolution at the interplay between speciation, adaptation to anthropic pressures and symbiotic interactions.

Underwater sampling in action: A researcher collects the specimen used to generate the reference genome. Photos by F. Zuberer.

Thanks to the ERGA community and the Biodiversity Genomics Europe Project, a high-quality reference genome of E. cavolini is now available, with a length around 500 Mb (1/6 of human genome) and 17 chromosomes (click here to read the genome report). We will work on understanding how this species can thrive near sewage outfalls or ancient industrial remnants, in the vicinity of Marseille. The results will also be useful to question the past and future evolution of Mediterranean octocorals facing climate change.

Read the peer-reviewed genome report of Eunicella cavolini (Aurelle et al., 2025): https://open-research-europe.ec.europa.eu/articles/5-323. Click here to learn more about ERGA’s standardized genome reports.

This project involves collaborations with CIIMAR (Jean-Baptiste Ledoux), MNHN-ISYEB (Sarah Samadi), IFREMER (Stéphane Sartoretto), OSU-Pythéas (Dorian Guillemain & Frédéric Zuberer) and IMBE (Alex Baumel & Vinciane Mossion).

References:

  • Aurelle, D., Guillemain, D., Zuberer, F., Malengros, D., Böhne, A., Monteiro, R., … & Bortoluzzi, C. (2025). ERGA-BGE reference genome of Eunicella cavolini, an IUCN Near Threatened Gorgonian of the Mediterranean Sea. Open Research Europe, 5, 323.
  • Kipson, S., Cerrano, C., Terrón-Sigler, A., Linares, C.L. & Ozalp, B. 2015. Eunicella cavolini (Mediterranean assessment). The IUCN Red List of Threatened Species 2015: e.T50012182A50606230. Accessed on 05 December 2025.

⏯️ Learn more about the species and genome applications in this short flash talk by Didier Aurelle: