Mygalomorph spiders represent a diverse, yet understudied lineage for which genomic level data has only recently become accessible through high-throughput genomic and transcriptomic sequencing methods. The Aptostichus atomarius species complex (family Euctenizidae) includes two coastal dune endemic members, each with inland sister species – affording exploration of dune adaptation associated patterns at the transcriptomic level. We apply an RNAseq approach to examine gene family conservation across the species complex and test for patterns of positive selection along branches leading to dune endemic species. An average of ~ 44,000 contigs were assembled for eight spiders representing dune (n = 2), inland (n = 4), and atomarius species complex outgroup taxa (n = 2). Transcriptomes were estimated to be 64% complete on average with 77 spider reference orthologs missing from all taxa. Over 18,000 orthologous gene clusters were identified within the atomarius complex members, > 5000 were detected in all species, and ~ 4700 were shared between species complex members and outgroup Aptostichus species. Gene family analysis with the FUSTr pipeline identified 47 gene families appearing to be under selection in the atomarius ingroup; four of the five top clusters include sequences strongly resembling other arthropod venom peptides. The COATS pipeline identified six gene clusters under positive selection on branches leading to dune species, three of which reflected the preferred species tree. Genes under selection were identified as Cytochrome P450 2c15 (also recovered in the FUSTr analysis), Niemann 2 Pick C1-like, and Kainate 2 isoform X1. We have generated eight draft transcriptomes for a closely related and ecologically diverse group of trapdoor spiders, identifying venom gene families potentially under selection across the Aptostichus atomarius complex and chemosensory-associated gene families under selection in dune endemic lineages.

中文翻译：

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移动进化沙：Aptostichusatomarius物种复合体的转录组表征。


Mygalomorph 蜘蛛代表了一个多样化但尚未得到充分研究的谱系，其基因组水平数据直到最近才通过高通量基因组和转录组测序方法获得。 Aptostichusatomarius 物种复合体（Euctenizidae 科）包括两个沿海沙丘特有成员，每个成员都有内陆姐妹物种 - 在转录组水平上探索沙丘适应相关模式。我们应用 RNAseq 方法来检查整个物种复合体中基因家族的保守性，并测试沿着导致沙丘特有物种的分支的正选择模式。代表沙丘 (n = 2)、内陆 (n = 4) 和原子物种复杂外类群 (n = 2) 的八只蜘蛛平均组装了约 44,000 个重叠群。转录组估计平均完整度为 64%，所有分类群中均缺失 77 个蜘蛛参考直向同源物。在atomarius复合体成员中鉴定出超过18,000个直系同源基因簇，在所有物种中检测到> 5000个，并且在物种复合体成员和外群Aptostichus物种之间共享约4700个基因簇。使用 FUSTr 管道进行基因家族分析，确定了 47 个基因家族似乎在 Atomarius 内群中处于选择状态；前五个簇中的四个包含与其他节肢动物毒液肽非常相似的序列。 COATS 管道在导致沙丘物种的分支上确定了六个受到正选择的基因簇，其中三个反映了首选物种树。选择的基因被鉴定为细胞色素 P450 2c15（也在 FUSTr 分析中恢复）、Niemann 2 Pick C1 样和 Kainate 2 同种型 X1。 我们为密切相关且生态多样化的活板门蜘蛛群体生成了八个转录组草稿，识别了可能在 Aptostichusatomarius 复合体中选择的毒液基因家族，以及在沙丘地方性谱系中选择的化学感应相关基因家族。