Long read, high-coverage reference genome of the Nymphalid butterfly Catonephele acontius (Nymphalidae: Biblidinae)

Background

Catonephele acontius (Nymphalidae:Biblidinae:Epicalinii) is a butterfly species with a wide distribution across the Neotropics including the Amazon. Here, we present a long-read high-coverage reference genome for this species to serve as a genomic resource for future studies on Biblidinae butterflies, a group that is the subject of ongoing studies of seasonal adaptation under climate change.

Results

We used PacBio HiFi and Isoseq reads to generate a highly contiguous and well-annotated reference genome. Five libraries were constructed, four using RNA from different tissues and one using High Molecular Weight (HMW) DNA from a wild-caught female. The DNA was sequenced using PacBio HiFi technology and the RNA was sequenced using long read PacBio IsoSeq technology. 20Gb of raw HiFi data was generated and assembled to an initial size of 520.7Mb (39x homozygous coverage) in 90 contigs. The assembly was then polished and decontaminated into 40 contigs with an N50 of 19.927Mb (BUSCO completeness: 99.0%, duplication 0.5%, fragmentation 0.7% and missing 0.3%). Final assembly size was 519.2Mb. Repeats were annotated, showing that the genome consisted of 40.4% transposable elements. IsoSeq transcriptome data from antennae, leg, ovary and digestive tissue was then used to structurally and functionally annotate gene models for the softmasked genome, uncovering ∼18,500 genes, with 70% of them given functional annotation.

Conclusions

This reference assembly joins many published genomes in the Nymphalidae family but represents one of the first high-quality genomes from the Biblidinae subfamily. It provides a valuable resource to study the evolution of plastic and seasonal traits and will help investigate the genetic processes that may influence this species responses to rapid climate change.