The Genome of an Ocean Wanderer: A High‐Quality Long‐Read Reference Genome for the Trindade Petrel ( Pterodroma arminjoniana )

ABSTRACT

The Trindade petrel ( Pterodroma arminjoniana ) is a procellariiform seabird found on Trindade Island in the South Atlantic Ocean. Recent evidence suggests that it also ranges and breeds across the Western Indian and South Pacific Oceans, where it hybridises with closely related species. The fitness effects of hybridisation, and the extent to which these might vary among populations, have yet to be studied in detail. Some populations contain seasonally distinct breeding sub‐populations, but the causes and consequences of this variation are unknown. While whole‐genome sequencing (WGS) is revolutionising our understanding of eco‐evolutionary processes such as hybridisation and local adaptation, there is a lack of high‐quality reference genomes in the Trindade petrel clade. Until recently, whole‐genome assemblies in Pterodroma petrels were limited to a small number of species and were largely based on short‐read sequencing. Oxford Nanopore Technology (ONT) is enabling long‐read sequencing of non‐model species, and this approach has recently been used to generate a high‐quality reference genome for Pterodroma . Here, we use ONT to produce a high‐quality long‐read reference genome for P. arminjoniana . We first generated a de novo assembly that we then scaffolded using the reference genome of a closely related species, the Cory's shearwater ( Calonectris borealis ). The resulting assembly, generated from a male bird, was 1.25 Gbp in size, had a scaffold N50 of 85 Mbp, and a BUSCO completeness score of 97.6%. Our annotation identified 18,099 protein‐coding genes, of which 92.1% corresponded to lineage‐consistent avian gene families, and no contamination was detected. We also compared the new reference with other Pterodroma genomes using a multispecies‐coalescent phylogenomic analysis. Our P. arminjoniana reference genome will be a valuable resource for ecological and evolutionary studies of this species and its close relatives, as well as for comparative genomic research on Procellariiformes more generally.