Genome Report: De novo genome assembly of the greater Bermuda land snail, Poecilozonites bermudensis (Mollusca:Gastropoda), confirms ancestral genome duplication

Abstract

Poecilozonites bermudensis, the greater Bermuda land snail, is a critically endangered species and one of only two extant members in its genus. These snails are one of Bermudas few endemic animal clades and their rich fossil record was the basis for the punctuated equilibria model of speciation. Once thought extinct, recent conservation efforts have focused on the recovery of the species, yet no genomic information or other molecular sequences have been available to inform these initiatives. We present a high-quality, annotated genome for P. bermudensis generated using PacBio long read and Omni-C short read sequencing. The resulting assembly is approximately 1.36 Gb with a scaffold N50 of 44.t Mb and 31 chromosome-length scaffolds. Nearly 43 percent of the genome was identified as repeat content. This assembly will serve as a resource for the conservation and study of P. bermudensis, and its only close extant and also critically endangered relative, P. circumfirmatus. Additionally, this genome adds to the growing body of data needed for a more complete understanding of gastropod evolution and for evolutionary processes in general. Article summaryThis paper is aimed primarily at researchers studying genomic evolution and phylogenetics of mollusks, and secondarily researchers studying evolution and conservation of Bermuda land snails. It reports not only the first genome sequence for the Bermuda land snails, but the first sequence of any kind from the group and the first genome from the larger clade to which they belong. The paper presents a complete de novo genome annotation and first order analyses. The results support previous hypotheses that a genome duplication occurred at the base of land snails, and they facilitate future molecular work on Bermudian and other snails.