Department of Biology, University of Wisconsin Oshkosh, Oshkosh, WI, USA.
Department of Biology, Lund University, Lund, Sweden.
Insect Mol Biol. 2020 Feb;29(1):77-91. doi: 10.1111/imb.12611. Epub 2019 Aug 20.
The insect odorant receptors (ORs) are amongst the largest gene families in insect genomes and the primary means by which insects recognize volatile compounds. The evolution of ORs is thus instrumental in explaining the chemical ecology of insects and as a model of evolutionary biology. However, although ORs have been described from numerous insect species, their analysis within and amongst the insect orders has been hindered by a combination of limited genomic information and a tendency of the OR family toward rapid divergence, gain, and loss. We addressed these issues in the insect order Coleoptera through a targeted genomic annotation effort that included 1181 ORs from one species of the sister order Strepsiptera and 10 species representing the four coleopteran suborders. The numbers of ORs in each species varied from hundreds to fewer than 10, but coleopteran ORs could nevertheless be represented within a scheme of nine monophyletic subfamilies. We observed many radiations and losses of genes amongst OR subfamilies, and the diversity of ORs appeared to parallel the host breadth of the study species. However, some small lineages of ORs persisted amongst many coleopteran families, suggesting receptors of key function that underlie the olfactory ecology of beetles.
昆虫气味受体（ORs）是昆虫基因组中最大的基因家族之一，也是昆虫识别挥发性化合物的主要手段。因此，ORs 的进化对于解释昆虫的化学生态学以及作为进化生物学的模型具有重要意义。然而，尽管已经从许多昆虫物种中描述了 ORs，但由于基因组信息有限以及 OR 家族快速分化、增益和丢失的倾向，它们在昆虫目之间的分析受到了阻碍。我们通过针对鞘翅目昆虫的目标基因组注释工作解决了这些问题，该工作包括来自缨尾目（Strepsiptera）的一个物种的 1181 个 OR 和代表四个鞘翅目亚目的 10 个物种。每个物种的 OR 数量从数百个到不到 10 个不等，但鞘翅目 OR 仍然可以用九个单系亚科的方案来表示。我们观察到 OR 亚科之间存在许多辐射和基因丢失，并且 OR 的多样性似乎与研究物种的宿主范围平行。然而，一些 OR 的小谱系在许多鞘翅目科之间持续存在，这表明这些 OR 具有关键功能，是甲虫嗅觉生态学的基础。
