Shobha Patil, Tobias Neumann, Julio Rozas, William J. Gillis, Nicholas H. Putman, Elizabeth A. Goodwin-Horn, Jerome H.L. Hui, Andrew M. Schurko, Jiaxin Qu, François Lapraz, Peshtewani K. Aqrawi, DeNard Simmons, Michael Holder, Maria Ninova, Sam Griffiths-Jones, Dieter Ebert, Huaiyang Jiang, Jack E. Green, Shalini N. Jhangiani, Sai Gubbala, Zivkos Apostolou, Luke Hayden, Wallace Arthur, Liezl Francisco, Kim C. Worley, Marcus Coyle, Claudio R. Alonso, Peter D. Evans, Viktoriya Korchina, Montserrat Torres-Oliva, Ling-Ling Pu, Sophie Helbing, Eckart Stolle, Judith H. Willis, Christopher Pham, Pedro Patraquim, Nehad Saada, Yuanqing Wu, Christie Kovar, David E. K. Ferrier, Nathan J. Kenny, Dinh Ngoc Ngo, James M Williams, Cornelius Eibner, Kenneth W. Siggens, Tittu Mathew, Ariel D. Chipman, Robert Mata, Vera S. Hunnekuhl, Cornelis J. P. Grimmelikhuijzen, Tamsin E. M. Jones, Kristin Tessmar-Raible, Olivia Mendivil Ramos, Xiaoyan Zou, Divya Kalra, Stephen Richards, Louis Du Pasquier, Marco Mariotti, Hugh M. Robertson, Jennifer C. J. Barna, Michael Akam, Geoffrey Okwuonu, Matthew Ronshaugen, Arndt von Haeseler, Julia P. Hunn, Francisca C. Almeida, Daniela Brites, Maximilian J. Telford, Galina Erikson, William J. Palmer, Francis M. Jiggins, Kerstin P. Blankenburg, Tobias S. Kaiser, Toni Gabaldón, Helen E. Robertson, Maurijn van der Zee, Rebecca Thornton, Donna M. Muzny, Peter K. Dearden, Richard A. Gibbs, Gerard Manning, Elizabeth J. Duncan, LaRonda Jackson, Daniel S.T. Hughes, Steven E. Scherer, Reinhard Schröder, Paul Havlak, Daniel Lawson, Carlo Brena, Fiona Ongeri, Frank Hauser, Anna Stief, Mehwish Javaid, Salvador Capella-Gutierrez, Jie Lv, F. Bernhard Kraus, Irene Newsham, Roderic Guigó, Alejandro Sánchez-Gracia, Sandra L. Lee, Nadia Znassi, Yi Han, Catherine Rabouille, Adelaide C. Rhodes, Christigale Mandapat, Cassandra G. Extavour, Jiggins, Francis [0000-0001-7470-8157], Akam, Michael [0000-0003-0063-2297], Apollo - University of Cambridge Repository, Hubrecht Institute for Developmental Biology and Stem Cell Research, University of St Andrews. School of Biology, University of St Andrews. Marine Alliance for Science & Technology Scotland, and University of St Andrews. Scottish Oceans Institute
Myriapods (e.g., centipedes and millipedes) display a simple homonomous body plan relative to other arthropods. All members of the class are terrestrial, but they attained terrestriality independently of insects. Myriapoda is the only arthropod class not represented by a sequenced genome. We present an analysis of the genome of the centipede Strigamia maritima. It retains a compact genome that has undergone less gene loss and shuffling than previously sequenced arthropods, and many orthologues of genes conserved from the bilaterian ancestor that have been lost in insects. Our analysis locates many genes in conserved macro-synteny contexts, and many small-scale examples of gene clustering. We describe several examples where S. maritima shows different solutions from insects to similar problems. The insect olfactory receptor gene family is absent from S. maritima, and olfaction in air is likely effected by expansion of other receptor gene families. For some genes S. maritima has evolved paralogues to generate coding sequence diversity, where insects use alternate splicing. This is most striking for the Dscam gene, which in Drosophila generates more than 100,000 alternate splice forms, but in S. maritima is encoded by over 100 paralogues. We see an intriguing linkage between the absence of any known photosensory proteins in a blind organism and the additional absence of canonical circadian clock genes. The phylogenetic position of myriapods allows us to identify where in arthropod phylogeny several particular molecular mechanisms and traits emerged. For example, we conclude that juvenile hormone signalling evolved with the emergence of the exoskeleton in the arthropods and that RR-1 containing cuticle proteins evolved in the lineage leading to Mandibulata. We also identify when various gene expansions and losses occurred. The genome of S. maritima offers us a unique glimpse into the ancestral arthropod genome, while also displaying many adaptations to its specific life history., Author Summary Arthropods are the most abundant animals on earth. Among them, insects clearly dominate on land, whereas crustaceans hold the title for the most diverse invertebrates in the oceans. Much is known about the biology of these groups, not least because of genomic studies of the fruit fly Drosophila, the water flea Daphnia, and other species used in research. Here we report the first genome sequence from a species belonging to a lineage that has previously received very little attention—the myriapods. Myriapods were among the first arthropods to invade the land over 400 million years ago, and survive today as the herbivorous millipedes and venomous centipedes, one of which—Strigamia maritima—we have sequenced here. We find that the genome of this centipede retains more characteristics of the presumed arthropod ancestor than other sequenced insect genomes. The genome provides access to many aspects of myriapod biology that have not been studied before, suggesting, for example, that they have diversified receptors for smell that are quite different from those used by insects. In addition, it shows specific consequences of the largely subterranean life of this particular species, which seems to have lost the genes for all known light-sensing molecules, even though it still avoids light.