School of Biomedical Sciences, Kent State University, Kent, OH 44240, USA.
Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA.
G3 (Bethesda). 2022 Feb 4;12(2). doi: 10.1093/g3journal/jkab414.
The invasive avian vampire fly (Philornis downsi, Diptera: Muscidae) is considered one of the greatest threats to the endemic avifauna of the Galápagos Islands. The fly larvae parasitize nearly every passerine species, including Darwin's finches. Most P. downsi research to date has focused on the effects of the fly on avian host fitness and mitigation methods. A lag in research related to the genetics of this invasion demonstrates, in part, the need to develop full-scale genomic resources with which to address further questions within this system. In this study, an adult female P. downsi was sequenced to generate a high-quality genome assembly. We examined various features of the genome (e.g., coding regions and noncoding transposable elements) and carried out comparative genomics analysis against other dipteran genomes. We identified lists of gene families that are significantly expanding or contracting in P. downsi that are related to insecticide resistance, detoxification, and counter defense against host immune responses. The P. downsi genome assembly provides an important resource for studying the molecular basis of successful invasion in the Galápagos and the dynamics of its population across multiple islands. The findings of significantly changing gene families associated with insecticide resistance and immune responses highlight the need for further investigations into the role of different gene families in aiding the fly's successful invasion. Furthermore, this genomic resource provides a necessary tool to better inform future research studies and mitigation strategies aimed at minimizing the fly's impact on Galápagos birds.
入侵性的鸟类吸血蝇（Philornis downsi，双翅目：蝇科）被认为是加拉帕戈斯群岛特有鸟类的最大威胁之一。蝇幼虫寄生在几乎所有雀形目物种中，包括达尔文雀。迄今为止，大多数关于 P. downsi 的研究都集中在蝇对鸟类宿主适应性和减轻影响的方法上。关于这种入侵的遗传学研究滞后部分表明，需要开发全面的基因组资源，以解决该系统内的进一步问题。在这项研究中，对一只成年雌性 P. downsi 进行了测序，以生成高质量的基因组组装。我们检查了基因组的各种特征（例如编码区域和非编码转座元件），并对其他双翅目基因组进行了比较基因组分析。我们确定了与杀虫剂抗性、解毒和针对宿主免疫反应的反击防御相关的显著扩张或收缩的基因家族列表。P. downsi 基因组组装为研究加拉帕戈斯群岛成功入侵的分子基础以及其在多个岛屿上的种群动态提供了重要资源。与杀虫剂抗性和免疫反应相关的显著变化的基因家族的发现，强调了进一步研究不同基因家族在帮助蝇成功入侵方面的作用的必要性。此外，这种基因组资源为未来旨在最小化蝇对加拉帕戈斯鸟类影响的研究和缓解策略提供了必要的工具。
