Event Abstract Back to Event Why animals (and fish in particular) abandon sex? On the interconnection between asexuality, hybridization, polyploidy and speciation Karel Janko1* 1 Institute of Animal Physiology and Genetics (ASCR), Czechia Although genetic machinery controlling production of recombined gametes is conserved, it has been repeatedly disrupted in all plant and animal phyla, including fish, leading to emergences of organisms, which possess a wide array of gametogenetic aberrations more or less alleviating the classical sexual reproduction. Despite intensive investigation, little is known about the proximate mechanisms which made these so-called asexual lineages switching from sex to asexuality. In this talk, I summarize up-to-date progress in knowledge and how our research contributed to understanding molecular and cytogenetic mechanisms triggering the emergence of asexual reproduction. In particular, I will focus on a question why the distortion of reproductive modes towards asexuality is often bound to interspecific hybridization. As a model organism we use loach fishes (Cobitidae) with several species pairs forming independent hybrid zones and producing wide array of hybrid forms ranging from sexual, through (hemi)clonal to sterile ones. Comparative analysis of hybrids and parental species employing phylogenomics, gene expression profiling and experimental crossings along with functional analyses of the gametogenetic pathways, provided some general clues explaining the link between hybridization and asexuality. First, clonal gametogenesis is not restricted to only some ‘pre-adapted’ parental genomes, but evolves gradually as a side-effect of accumulation of reproductive incompatibilities between species. Hybrid’s asexuality may thus be viewed as a special type of Bateson-Dobzhansky-Muller incompatibility. Second, successful establishment of hybrid clones requires certain level of cis-regulatory divergence between parental genomes, which ensures partially independent execution of co-inherited developmental programs in hybrids. We further revealed that the efficiency of trans regulatory pathways in a hybrid were systematically affected by polyploidization, which explain why polyploidy is so common among asexuals. Finally, asexuality typically emerges in one hybrid sex but evolves hand-in-hand with sterility of the other hybrid’s sex. Although various types of epistatic incompatibilities are likely involved in independent cases of sterility and clonality, they are developmentally canalized into only several types of gametogenetic aberrations. Our study points at tight association between asexuality and other postzygotic reproductive barriers. Acknowledgements We are grateful for financial support from the Czech Academy of Sciences of the Czech Republic grant no. RVO67985904, Czech Science Foundation grant nos. 13-12580S, 17-09807S,19-21552S Keywords: speciation, Parthenogenesis, Polyploidy, Cobitis, hybridization Conference: XVI European Congress of Ichthyology, Lausanne, Switzerland, 2 Sep - 6 Sep, 2019. Presentation Type: Oral Topic: EVOLUTION AND ECOLOGY OF FISH WITH ASEXUAL REPRODUCTION, HYBRID COMPLEXES AND POLYPLOIDY, WITH SPECIAL FOCUS ON LOACHES (COBITOIDEI) Citation: Janko K (2019). Why animals (and fish in particular) abandon sex? On the interconnection between asexuality, hybridization, polyploidy and speciation. Front. Mar. Sci. Conference Abstract: XVI European Congress of Ichthyology. doi: 10.3389/conf.fmars.2019.07.00030 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 06 Jun 2019; Published Online: 14 Aug 2019. * Correspondence: Dr. Karel Janko, Institute of Animal Physiology and Genetics (ASCR), Prague, Czechia, janko@iapg.cas.cz Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Karel Janko Google Karel Janko Google Scholar Karel Janko PubMed Karel Janko Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.