bioRxiv preprint doi: https://doi.org/10.1101/567719; this version posted March 5, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Lowe et al., March 01 2019 – preprint copy - BioRxiv A cis-regulatory change underlying the motor neuron-specific loss of terminal selector gene expression in immotile tunicate larvae Elijah K. Lowe1,2, Claudia Racioppi2,3, Nadine Peyriéras2,4,5, Filomena Ristoratore2,6, Lionel Christiaen2,3, Billie J. Swalla2,7,8, & Alberto Stolfi1,2* 1. School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA. 2. Station Biologique de Roscoff, Roscoff, France. 3. Center for Developmental Genetics, Department of Biology, New York University, New York, NY, USA. 4. UPS3611 Complex Systems Institute Paris Île-de-France (ISC-PIF), CNRS, Paris, France. 5. USR3695 BioEmergences, CNRS, Paris-Saclay University, Gif-sur-Yvette, France. 6. Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Naples, Italy. 7. Department of Biology, University of Washington, Seattle, WA, USA. 8. Friday Harbor Laboratories, University of Washington, Friday Harbor, WA, USA. * Corresponding author:
[email protected] Abstract The evolutionary history of animal body plans cannot be fully reconstructed without considering the roles of both novelties and losses. Some of the more remarkable examples of massively parallel evolutionary losses in animals comes from many species in the tunicate genus Molgula that have independently lost the swimming larva and instead develop as tail-less, immotile larvae that bypass the period of swimming and dispersal observed in other tunicates, marine invertebrate chordates that alternate between motile larval and sessile adult life cycle stages.