Fraire-Zamora, Juan JoséJaeger, Johannes, 1973-Solon, Jérôme2019-11-142019-11-142018Fraire-Zamora JJ, Jaeger J, Solon J. Two consecutive microtubule-based epithelial seaming events mediate dorsal closure in the scuttle fly Megaselia abdita. eLife 2018;7:e33807. DOI: 10.7554/eLife.338072050-084Xhttp://hdl.handle.net/10230/42847Evolution of morphogenesis is generally associated with changes in genetic regulation. Here, we report evidence indicating that dorsal closure, a conserved morphogenetic process in dipterans, evolved as the consequence of rearrangements in epithelial organization rather than signaling regulation. In Drosophila melanogaster, dorsal closure consists of a two-tissue system where the contraction of extraembryonic amnioserosa and a JNK/Dpp-dependent epidermal actomyosin cable result in microtubule-dependent seaming of the epidermis. We find that dorsal closure in Megaselia abdita, a three-tissue system comprising serosa, amnion and epidermis, differs in morphogenetic rearrangements despite conservation of JNK/Dpp signaling. In addition to an actomyosin cable, M. abdita dorsal closure is driven by the rupture and contraction of the serosa and the consecutive microtubule-dependent seaming of amnion and epidermis. Our study indicates that the evolutionary transition to a reduced system of dorsal closure involves simplification of the seaming process without changing the signaling pathways of closure progression.application/pdfeng© 2018, Fraire-Zamora et al. This article is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use and redistribution provided that the original author and source are credited.info:eu-repo/semantics/articlehttp://dx.doi.org/10.7554/eLife.33807Megaselia abditaDevelopmental biologyDorsal closureEvolution of development (evo-devo)Evolutionary biologyExtraembryonic tissue (serosa/amnion)GenomicsMicrotubule cytoskeletonStem cellsTissue seaminginfo:eu-repo/semantics/openAccess