Chromosome-level genome assembly and transcriptome analysis of the Ural owl, Strix uralensis Pallas, 1771.

The Ural owl (Strix uralensis) is a large member of the Strigidae family and inhabits Eurasian forests from Germany to Japan. However, it faces increased range reduction, particularly at its southwestern distribution edges. Despite being considered "Least Concern" by the IUCN, local populations have become threatened in Central Europe due to severe habitat loss. Reintroduction programs aim to restore these populations by closing distribution gaps and facilitating natural recolonization of suitable habitats. To support these efforts, genomic resources have become an established tool to assess genetic diversity, geographic structure, and potential inbreeding, crucial for maintaining the genetic health and adaptability of newly established populations. Here, we present a de novo genome assembly and transcriptome of the Ural owl based on ONT long-reads, Omni-C Illumina short-reads, and RNASeq data. The final assembly has a total length of 1.26 Gb, of which 96.42% is anchored into the 42 largest scaffolds. The scaffold and contig N50 values of 88.65 Mb and 21.74 Mb, respectively, a BUSCO/compleasm completeness of 97.5%/99.65% and k-mer completeness of 95.18%, emphasize the high quality of this assembly. Furthermore, annotation of the assembly identified 17,650 genes and a repeat content of 12.48%. This new highly contiguous and chromosome-level assembly will greatly benefit Ural owl conservation management by informing reintroduction programs about the species' genetic health and contributing a valuable resource to study genetic function in greater detail across the whole Strigidae family.