TY - JOUR TI - Embryonic origin and serial homology of gill arches and paired fins in the skate, Leucoraja erinacea AU - Sleight, Victoria A AU - Gillis, J Andrew A2 - Tulenko, Frank A2 - Stainier, Didier YR A2 - Sefton, Elizabeth M A2 - Cerny, Robert VL - 9 PY - 2020 DA - 2020/11/17 SP - e60635 C1 - eLife 2020;9:e60635 DO - 10.7554/eLife.60635 UR - https://doi.org/10.7554/eLife.60635 AB - Paired fins are a defining feature of the jawed vertebrate body plan, but their evolutionary origin remains unresolved. Gegenbaur proposed that paired fins evolved as gill arch serial homologues, but this hypothesis is now widely discounted, owing largely to the presumed distinct embryonic origins of these structures from mesoderm and neural crest, respectively. Here, we use cell lineage tracing to test the embryonic origin of the pharyngeal and paired fin skeleton in the skate (Leucoraja erinacea). We find that while the jaw and hyoid arch skeleton derive from neural crest, and the pectoral fin skeleton from mesoderm, the gill arches are of dual origin, receiving contributions from both germ layers. We propose that gill arches and paired fins are serially homologous as derivatives of a continuous, dual-origin mesenchyme with common skeletogenic competence, and that this serial homology accounts for their parallel anatomical organization and shared responses to axial patterning signals. KW - little skate KW - Leucoraja erinacea KW - Neural crest KW - Mesoderm KW - gill arch KW - paired appendages KW - serial homology JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -