Long-reads are revolutionizing 20 years of insect genome sequencing

Abstract

The first insect genome (Drosophila melanogaster) was published two decades ago. Today, nuclear genome assemblies are available for a staggering 601 insect species representing 20 orders. In this study, we analyzed the most-contiguous assembly for each species and provide a "state of the field" perspective, emphasizing taxonomic representation, assembly quality, gene completeness, and sequencing technologies. Relative to species richness, genomic efforts have been biased towards four orders (Diptera, Hymenoptera, Collembola, and Phasmatodea), Coleoptera are underrepresented, and 11 orders still lack a publicly available genome assembly. The average insect genome assembly is 439.2 megabases in length with 87.5% of single-copy benchmarking genes intact. Most notable has been the impact of long-read sequencing; assemblies that incorporate long-reads are ~48x more contiguous than those that do not. We offer four recommendations as we collectively continue building insect genome resources: (1) seek better integration between independent research groups and consortia, (2) balance future sampling between filling taxonomic gaps and generating data for targeted questions, (3) take advantage of long read sequencing technologies, and (4) expand and improve gene annotations. Significance statementSince the first insect genome was sequenced ~20 years ago, sequencing technologies and the availability of insect genome assemblies have both advanced dramatically. In this study, we curated, analyzed, and summarized the field of insect genomics in terms of taxonomic representation, assembly quality, gene completeness, and sequencing technology. We show that 601 insect species have genome assemblies available, with some groups heavily overrepresented (e.g., Diptera) relative to others (e.g., Coleoptera). The major takeaway of our study is that genome assemblies produced with long reads are ~48x more contiguous than short read assemblies.