The insect order Psocodea is a diverse lineage comprising both parasitic (Phthiraptera) and non-parasitic members (Psocoptera). The extreme age and ecological diversity of the group may be associated with major genomic changes, such as base compositional biases expected to affect phylogenetic inference. Divergent morphology between parasitic and non-parasitic members has also obscured the origins of parasitism within the order. We conducted a phylogenomic analysis on the order Psocodea utilizing both transcriptome and genome sequencing to obtain a data set of 2,370 orthologous genes. All phylogenomic analyses, including both concatenated and coalescent methods suggest a single origin of parasitism within the order Psocodea, resolving conflicting results from previous studies. This phylogeny allows us to propose a stable ordinal level classification scheme that retains significant taxonomic names present in historical scientific literature and reflects the evolution of the group as a whole. A dating analysis, with internal nodes calibrated by fossil evidence, suggests an origin of parasitism that predates the K-Pg boundary. Nucleotide compositional biases are detected in third and first codon positions and result in the anomalous placement of the Amphientometae as sister to Psocomorpha when all nucleotide sites are analyzed. Likelihood-mapping and quartet sampling methods demonstrate that base compositional biases can also have an effect on quartet-based methods.

中文翻译：

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寄生和非寄生虱子的系统基因组学（昆虫纲：Psocodea）：在下一代数据集中结合序列数据和探索成分偏差解决方案

昆虫目 Psocodea 是一个多样化的谱系，包括寄生 (Phthiraptera) 和非寄生成员 (Psooptera)。该群体的极端年龄和生态多样性可能与主要的基因组变化有关，例如预计会影响系统发育推断的碱基组成偏差。寄生和非寄生成员之间的不同形态也掩盖了该目内寄生的起源。我们利用转录组和基因组测序对 Psocodea 目进行了系统发育分析，以获得 2,370 个直系同源基因的数据集。所有系统发育分析，包括串联和合并方法，都表明 Psocodea 目内的单一寄生起源，解决了先前研究中相互矛盾的结果。这种系统发育使我们能够提出一个稳定的有序级别分类方案，该方案保留了历史科学文献中存在的重要分类名称，并反映了整个群体的演变。用化石证据校准的内部节点的测年分析表明寄生的起源早于 K-Pg 边界。在第三个和第一个密码子位置检测到核苷酸组成偏差，并在分析所有核苷酸位点时导致 Amphientometae 作为 Psocomorpha 的姐妹的异常放置。似然映射和四重采样方法表明，基础成分偏差也会对基于四重奏的方法产生影响。用化石证据校准的内部节点的测年分析表明寄生的起源早于 K-Pg 边界。在第三个和第一个密码子位置检测到核苷酸组成偏差，并在分析所有核苷酸位点时导致 Amphientometae 作为 Psocomorpha 的姐妹的异常放置。似然映射和四重采样方法表明，基础成分偏差也会对基于四重奏的方法产生影响。用化石证据校准的内部节点的测年分析表明寄生的起源早于 K-Pg 边界。在第三个和第一个密码子位置检测到核苷酸组成偏差，并在分析所有核苷酸位点时导致 Amphientometae 作为 Psocomorpha 的姐妹的异常放置。似然映射和四重采样方法表明，基础成分偏差也会对基于四重奏的方法产生影响。