Transcriptome assembly of Richtersius coronifer with annotated BLAST result against Ramazzottius varieornatus.

For transcriptome sequencing and assembly, total RNA was extracted from a single specimen of tardigrade using Direct-zol RNA kit (Zymo Research) and was amplified using SMARTer Ultra Low Input RNA Kit for Sequencing v.3 (Clonetech). Illumina libraries were prepared using KAPA HyperPlus Kit (KAPA BIosystems), and the library was sequenced using a NextSeq 500 High Output Mode 75 cycles kit (Illumina) as single-end 75bp layout. Protocols are detailed in Arakawa et al. (2016)andYoshida et al. (2018). Sequences were filtered for adapters and demultiplexed using the bcl2fastq v.2 software (Illumina), and were assembled <i>de novo</i>using Bridger software with default parameters (Chang et al. 2015). Completeness of the assembly was assessed using BUSCO v.2/3 transcriptome mode with Eukaryote reference through gVolante server (Nishimura et al. 2017). Gene content was compared with <i>Ramazzottius varieornatus</i>and <i>Hypsibius exemplaris </i>genomes (Yoshida et al. 2017), as well as <i>Drosophila melanogaster</i>and <i>Caenorhabditis elegans</i>reference proteomes obtained from Flybase and Wormbase, respectively. Annotated BLAST result to <i>R. varieornatus </i>reference proteome with BLASTX (-e 1e-5) is also provided with the transcriptome assembly.

本数据集围绕缓步动物转录组测序与组装实验构建：首先使用Direct-zol RNA试剂盒（Zymo Research公司）从1只缓步动物标本中提取总RNA，并采用SMARTer Ultra Low Input RNA Kit for Sequencing v.3（Clonetech公司）完成RNA扩增；随后使用KAPA HyperPlus试剂盒（KAPA BIosystems公司）构建Illumina测序文库，再通过NextSeq 500高通量输出模式75循环试剂盒（Illumina公司）以单端75bp的测序布局完成上机测序。详细实验流程参见Arakawa等人（2016）与Yoshida等人（2018）的研究。

测序下机数据先通过bcl2fastq v.2软件（Illumina公司）完成接头过滤与样本拆分，随后采用Bridger软件默认参数进行从头（de novo）组装（Chang等，2015）。通过gVolante服务器（Nishimura等，2017），使用BUSCO v2/3版本的转录组评估模式结合真核生物参考基因集，对组装结果的完整性进行评估。将该转录组的基因集与*Ramazzottius varieornatus*、*Hypsibius exemplaris*的基因组（Yoshida等，2017），以及分别从Flybase和Wormbase获取的*Drosophila melanogaster*（黑腹果蝇）、*Caenorhabditis elegans*（秀丽隐杆线虫）参考蛋白组进行比对分析。本数据集同时提供了针对*R. varieornatus*参考蛋白组的BLASTX注释结果（期望值阈值设为1e-5），该结果与转录组组装文件一并发布。