Symbiosis, Selection, and Novelty: Freshwater Adaptation in the Unique Sponges of Lake Baikal

Freshwater sponges of the family Lubomirskiidae, endemic to Lake Baikal, exhibit remarkable adaptations to extreme conditions, including thermal fluctuations, desiccation, anoxia, and pollutant resistance. A comparative genomic analysis of three Lubomirskiidae species revealed 61 orthogroups under positive selection, with key genes such as zinc transporters, transcription factors, and structural proteins driving evolutionary novelty in these sponges. The study also identified symbiotic relationships with unicellular algae, bacteria, and dinoflagellates, including Gyrodinium. By sequencing deep transcriptomes and a draft genome for Lubomirskia baikalensis, researchers uncovered molecular mechanisms underlying freshwater adaptation, providing insights into the ecological roles of these unique sponges.

Kenny, N. J., Plese, B., Riesgo, A., & Itskovich, V. B. (2019). Symbiosis, Selection, and Novelty: Freshwater Adaptation in the Unique Sponges of Lake Baikal. Molecular Biology and Evolution, 36(11), 2462–2480. https://doi.org/10.1093/molbev/msz151