Macias-Muñoz Aide, Varney Rebecca, Katcher Eva, Everhart Maia, Oakley Todd H
Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, USA.
Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA.
G3 (Bethesda). 2025 Jul 9;15(7). doi: 10.1093/g3journal/jkaf110.
As one of just a handful of nonbilaterian animal phyla, Cnidaria are key to understanding genome evolution across Metazoa. Despite their importance and diversity, the genomes of most species in the phylum are unsequenced, due in large part to difficulties cultivating them in a laboratory. Here, we present a genome sequence of Bougainvillia cf. muscus, a hydrozoan with 4 marginal bulbs each containing 7 simple eyes (ocelli). This species appeared in our tanks from contamination. While we lacked sufficient samples for transcriptomic or functional studies, we were able to expand our knowledge of how the genome of this species compares to the few, better studied members of hydrozoans by investigating synteny to other cnidarians, repetitive element content, and phylogenetics and synteny of vision-related genes in this eyed species compared to eyeless relatives. The genome sequence consists of 350 contigs with an N50 of 10 Mb, a total genome length of 375.328 Mb, a BUSCO score of 90.1%, and predicted protein coding genes totaling 46,431. We found a high degree of macrosynteny conservation with Hydra vulgaris, Hydractinia symbiolongicarpus, and Turritopsis rubra. Repetitive elements make up 62% of this Bougainvillia genome. For vision-related genes, we identified 20 cnidarian opsins (cnidops) in Bougainvillia and found instances of gene duplication and loss in families associated with bilaterian eye development, phototransduction, and visual cycling. This high-quality, contiguous genome in an eyed hydrozoan will be a valuable resource for additional comparative genomic studies.
作为仅有的少数非两侧对称动物门之一，刺胞动物门对于理解后生动物的基因组进化至关重要。尽管它们具有重要性和多样性，但该门中大多数物种的基因组尚未测序，这在很大程度上是由于在实验室中培养它们存在困难。在这里，我们展示了一种类似苔藓筒螅（Bougainvillia cf. muscus）的基因组序列，它是一种水螅虫，有4个边缘球茎，每个球茎包含7个单眼（眼点）。这个物种是因污染出现在我们的培养槽中的。虽然我们没有足够的样本进行转录组学或功能研究，但通过研究与其他刺胞动物的共线性、重复元件含量以及与无眼亲属相比该有眼物种中视觉相关基因的系统发育和共线性，我们能够扩展对该物种基因组与少数研究更深入的水螅虫成员相比情况的了解。该基因组序列由350个重叠群组成，N50为10 Mb，基因组总长度为375.328 Mb，BUSCO评分为90.1%，预测的蛋白质编码基因共有46,431个。我们发现它与普通水螅（Hydra vulgaris）、共生水母（Hydractinia symbiolongicarpus）和红色灯塔水母（Turritopsis rubra）有高度的宏观共线性保守性。重复元件占该筒螅基因组的62%。对于视觉相关基因，我们在筒螅中鉴定出20种刺胞动物视蛋白（刺胞视蛋白），并发现了与两侧对称动物眼睛发育、光转导和视觉循环相关的家族中存在基因重复和丢失的情况。这个有眼水螅虫的高质量连续基因组将成为额外比较基因组研究的宝贵资源。
