School of Biological and Environmental Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK.
School of Biological and Environmental Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK.
Mar Genomics. 2020 Oct;53:100753. doi: 10.1016/j.margen.2020.100753. Epub 2020 Feb 11.
The beadlet anemone Actinia equina (L.) (Cnidaria: Anthozoa: Actiniaria: Actiniidae) is one of the most familiar organisms of the North European intertidal zone. Once considered a single, morphologically variable species across northern Europe, it is now recognised as one member of a variable species complex. Previous studies of distribution, aggression, allozymes and mitochondrial DNA suggest that the diversity in form and colour within A. equina may hide still unrecognised species diversity. To empower further study of A. equina population genetics and systematics, we sequenced (PacBio Sequel) the genome of a single A. equina individual to produce a high-quality genome assembly (contig N = 492,607 bp, 1485 contigs, number of protein coding genes = 47,671, 97% BUSCO completeness). There is debate as to whether A. equina reproduces solely asexually, since no reliable, consistent evidence of sexual reproduction has been found. To gain further insight, we examined the genome for evidence of a 'meiotic toolkit' - genes believed to be found consistently in sexually reproducing organisms - and demonstrate that the A. equina genome appears not to have this full complement. Additionally, Smudgeplot analysis, coupled with high haplotype diversity, indicates this genome assembly to be of ambiguous ploidy, suggesting that A. equina may not be diploid. The suggested polyploid nature of this species coupled with the deficiency in meiotic toolkit genes, indicates that further field and laboratory studies of this species is warranted to understand how this species reproduces and what role ploidy may play in speciation within this speciose genus.
海葵 Actinia equina（L.）（刺胞动物门：珊瑚纲：海葵目：海葵科）是北欧潮间带最常见的生物之一。曾经被认为是北欧形态多样的单一物种，现在被认为是一个形态多变的物种复合体的一员。先前对分布、侵略性、同工酶和线粒体 DNA 的研究表明，A. equina 内部形态和颜色的多样性可能隐藏着尚未被识别的物种多样性。为了进一步研究 A. equina 的种群遗传学和系统发育，我们对单个 A. equina 个体进行了测序（PacBio Sequel），以产生高质量的基因组组装（片段 N = 492607 bp，1485 个片段，蛋白质编码基因数 = 47671 个，97%的 BUSCO 完整性）。关于 A. equina 是否仅通过无性繁殖进行繁殖存在争议，因为没有发现可靠、一致的有性繁殖证据。为了获得更深入的了解，我们检查了基因组中是否存在“减数分裂工具包”——被认为在有性繁殖生物中普遍存在的基因——并证明 A. equina 基因组似乎没有这个完整的基因。此外，Smudgeplot 分析结合高单倍型多样性表明，这个基因组组装的倍性不确定，这表明 A. equina 可能不是二倍体。该物种的多倍体性质加上减数分裂工具包基因的缺乏，表明需要进一步对该物种进行实地和实验室研究，以了解该物种如何繁殖以及多倍体在这个多态属的物种形成中可能扮演什么角色。
