The state of Medusozoa genomics: current evidence and future challenges

Abstract

Medusozoa is a widely distributed ancient lineage that harbors one-third of Cnidaria diversity divided into 4 classes. This clade is characterized by the succession of stages and modes of reproduction during metagenic lifecycles, and includes some of the most plastic body plans and life cycles among animals. The characterization of traditional genomic features, such as chromosome numbers and genome sizes, was rather overlooked in Medusozoa and many evolutionary questions still remain unanswered. Modern genomic DNA sequencing in this group started in 2010 with the publication of the Hydra vulgaris genome and has experienced an exponential increase in the past 3 years. Therefore, an update of the state of Medusozoa genomics is warranted. We reviewed different sources of evidence, including cytogenetic records and high-throughput sequencing projects. We focused on 4 main topics that would be relevant for the broad Cnidaria research community: (i) taxonomic coverage of genomic information; (ii) continuity, quality, and completeness of high-throughput sequencing datasets; (iii) overview of the Medusozoa specific research questions approached with genomics; and (iv) the accessibility of data and metadata. We highlight a lack of standardization in genomic projects and their reports, and reinforce a series of recommendations to enhance future collaborative research.

Genome-Scale Analysis Reveals Extensive Diversification of Voltage-Gated K+ Channels in Stem Cnidarians

“…There is now a wealth of sequence data available from cnidarians ( Alama-Bermejo and Holzer 2021 ; Quek and Huang 2022 ; Santander et al 2022 ), but we chose to limit our main comparisons of voltage-gated K + channels to eight species with high-quality genomes and transcriptomes because estimates of ancestral channel sets depend on having a relatively complete picture of the channel genes present in each species. The species we chose are listed along with a consensus phylogeny of Cnidaria in figure 2 and represent key evolutionary nodes that enable several important comparisons.…”

Novel technologies uncover novel ‘anti’-microbial peptides in Hydra shaping the species-specific microbiome

“…Recently, high-quality genome sequences became publicly available (see figure 1a) for two species of the 'brown hydra' phylogenetic group (Hydra vulgaris AEP and Hydra oligactis) [20], and one green hydra species (Hydra viridissima) [21], hence providing a glimpse into 200 Myr of evolutionary radiation within the Hydra crown group [3]. Additionally, a number of high-quality genomes of other hydrozoan cnidarians, scyphozoans and anthozoans became available [22][23][24][25][26].…”

Revisiting mitogenome evolution in Medusozoa with eight new mitochondrial genomes

“…More recently, advancements in genomic sequencing technologies have enabled large volumes of genomic data to be produced and analyzed, leading to a push toward phylogenomic reconstructions across the tree of life. 28 , 29 , 30 Consequently, proposed mitogenomic phylogeny hypotheses have also been more recently corroborated by nuclear phylogenomics. For instance, both nuclear 31 and mitogenomic 32 , 33 analyses show that Hydrozoa orders Anthoathecata and Leptothecata are paraphyletic groups and support the monophyly of subphylum Medusozoa.…”