Whole genome assembly and annotation of blackstripe livebearer Poeciliopsis prolifica.

The blackstripe livebearer Poeciliopsis prolifica is a live-bearing fish belonging to the family Poeciliidae with high level of post-fertilization maternal investment (matrotrophy). This viviparous matrotrophic species has evolved a structure similarly to the mammalian placenta. Placentas have independently evolved multiple times in Poeciliidae from non-placental ancestors, which provides an opportunity to study the placental evolution. However, there is a lack of high-quality reference genomes for the placental species in Poeciliidae. In this study, we present a 674 Mbp assembly of Poeciliopsis prolifica in 504 contigs with excellent continuity (contig N50 7.7 Mb) and completeness (97.2% BUSCO completeness score, including 92.6% single copy and 4.6% duplicated BUSCO score). A total of 27,227 protein-coding genes were annotated from the merged data sets based on bioinformatic prediction and RNA sequencing and homology evidence. Phylogenomic analyses revealed that Poeciliopsis prolifica diverged from the guppy (Poecilia reticulata) ∼19 million years ago. Our research provides the necessary resources and the genomic toolkit for investigating the genetic underpinning of placentation.