Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5242, Ecole Normale Supérieure de Lyon 46, allée d'Italie, 69364, Lyon Cedex 07, France.
Department of Molecular Genetics & Microbiology and UF Genetics Institute, University of Florida, 2033 Mowry Road, Gainesville, FL, 32610-3610, USA.
BMC Genomics. 2018 Nov 21;19(1):832. doi: 10.1186/s12864-018-5163-2.
Having conquered water surfaces worldwide, the semi-aquatic bugs occupy ponds, streams, lakes, mangroves, and even open oceans. The diversity of this group has inspired a range of scientific studies from ecology and evolution to developmental genetics and hydrodynamics of fluid locomotion. However, the lack of a representative water strider genome hinders our ability to more thoroughly investigate the molecular mechanisms underlying the processes of adaptation and diversification within this group.
Here we report the sequencing and manual annotation of the Gerris buenoi (G. buenoi) genome; the first water strider genome to be sequenced thus far. The size of the G. buenoi genome is approximately 1,000 Mb, and this sequencing effort has recovered 20,949 predicted protein-coding genes. Manual annotation uncovered a number of local (tandem and proximal) gene duplications and expansions of gene families known for their importance in a variety of processes associated with morphological and physiological adaptations to a water surface lifestyle. These expansions may affect key processes associated with growth, vision, desiccation resistance, detoxification, olfaction and epigenetic regulation. Strikingly, the G. buenoi genome contains three insulin receptors, suggesting key changes in the rewiring and function of the insulin pathway. Other genomic changes affecting with opsin genes may be associated with wavelength sensitivity shifts in opsins, which is likely to be key in facilitating specific adaptations in vision for diverse water habitats.
Our findings suggest that local gene duplications might have played an important role during the evolution of water striders. Along with these findings, the sequencing of the G. buenoi genome now provides us the opportunity to pursue exciting research opportunities to further understand the genomic underpinnings of traits associated with the extreme body plan and life history of water striders.
半水生昆虫已经征服了世界各地的水域，它们栖息在池塘、溪流、湖泊、红树林，甚至开阔的海洋中。这个群体的多样性激发了从生态学和进化到发育遗传学以及流体运动水动力等一系列科学研究。然而，由于缺乏代表性的水黾基因组，我们无法更深入地研究该群体中适应和多样化过程的分子机制。
我们在这里报告了 Gerris buenoi（G. buenoi）基因组的测序和手动注释；这是迄今为止测序的第一个水黾基因组。G. buenoi 基因组的大小约为 1000 Mb，这项测序工作共预测到了 20949 个编码蛋白的基因。手动注释揭示了一些局部（串联和邻近）基因重复和基因家族的扩增，这些基因家族在与形态和生理适应水面生活方式相关的多种过程中具有重要作用。这些扩张可能会影响与生长、视觉、抗干燥、解毒、嗅觉和表观遗传调控等关键过程相关的基因。引人注目的是，G. buenoi 基因组包含三个胰岛素受体，这表明胰岛素途径的重布线和功能发生了关键变化。其他影响视蛋白基因的基因组变化可能与视蛋白的波长敏感性变化有关，这可能是促进不同水生栖息地中视觉特定适应的关键。
我们的研究结果表明，局部基因重复可能在水黾的进化过程中发挥了重要作用。除了这些发现，G. buenoi 基因组的测序现在为我们提供了机会，以追求令人兴奋的研究机会，进一步了解与水黾极端身体计划和生活史相关特征的基因组基础。
