Oikopleura dioica culturing made easy: a low-cost facility for an emerging animal model in EvoDevo.

The genome sequencing and the development of RNAi knockdown technologies in the urochordate Oikopleura dioica are making this organism an attractive emergent model in the field of EvoDevo. To succeed as a new animal model, however, an organism needs to be easily and affordably cultured in the laboratory. Nowadays, there are only two facilities in the world capable to indefinitely maintain Oikopleura dioica, one in the SARS institute (Bergen, Norway) and the other in the Osaka University (Japan). Here, we describe the setup of a new facility in the University of Barcelona (Spain) in which we have modified previously published husbandry protocols to optimize the weekly production of thousands of embryos and hundreds of mature animals using the minimum amount of space, human resources, and technical equipment. This optimization includes novel protocols of cryopreservation and solid cultures for long-term maintenance of microalgal stocks-Chaetoceros calcitrans, Isochrysis sp., Rhinomonas reticulate, and Synechococcus sp.-needed for Oikopleura dioica feeding. Our culture system maintains partially inbred lines healthy with similar characteristics to wild animals, and it is easily expandable to satisfy on demand the needs of any laboratory that may wish to use Oikopleura dioica as a model organism.