“A chromosome-level reference genome for the colonial marine hydrozoan Podocoryna americana ”

Abstract

Cnidarians are important models for studying the evolution of animal development, regeneration, cell type differentiation, and allorecognition. The marine hydrozoan Podocoryna americana is related to the well-established model species Hydractinia symbiolongicarpus. Although both species possess a sessile polyp stage, P. americana differs in that it also has a free-swimming medusa (jellyfish) stage in its life cycle. We used a combination of PacBio CLR long-read and Illumina Hi-C short-read genome sequencing to produce a chromosome-level genome assembly for P. americana. The final assembly is 327 Mbp in total length with 17 chromosome-scale scaffolds representing 98% of the assembly. Comprehensive functional annotation with BRAKER3 generated a total of 19,085 predicted protein-coding genes in this assembly, covering 91.2% of the metazoan BUSCO gene set. Comparison of the P. americana genome to other chromosome-level cnidarian genome assemblies revealed a high degree of macrosynteny conservation, and ortholog identification and gene family evolution analysis identified 522 expanded and 1,026 contracted gene families in P. americana. This high-quality, chromosome-level genome assembly of P. americana will be an invaluable resource for researchers studying the evolution of development, regeneration, and allorecognition in cnidarians and other metazoans.