Genome assembly: We assembled the genome of the okapi from pacbio CLR reads using WTDBG2 v. 2.5 (Ruan & Li, 2019) using the preset for PacBio Sequel reads (flag '-x sq') followed by three iterations of long-read polishing with racon v.1.4.3 (Vaser et al., 2017) and three iterations of short-read polishing with pilon v.1.23 (Walker et al., 2014). The assembly was scaffolded into chromosome-scale scaffolds with the Dovetail Genomics´ HiRise pipeline (Putnam et al., 2016) using publically available Hi-C data (SRR8616855, SRR8616856). Subsequently, three iterations of gap-closing were performed using TGS-GapCloser v.1.1.1 (Xu et al., 2020). The resulting final assembly can be found under the filename: TBG_Okapi_asm_v1.fasta. Genome annotation: Prior to gene annotation, we used RepeatModeler v. 2.0.1 for the generation of a de novo repeat library. This library was combined with a Cetartiodactyla-specific (Flynn et al., 2020) library from RepBase (Bao et al., 2015) and used as a custom repeat library for the masking of repeats with RepeatMasker v.4.1.0 (http://www.repeatmasker.org/RMDownload.html). Interspersed repeats were hard-masked while simple repeats were soft-masked. The masked assembly file can be found under the filename: TBG_Okapi_asm_v1_hardmaskedTEs_softmaskedSR.fasta After repeat masking we used the GeMoMa pipeline v.1.7.1 (Keilwagen et al., 2016, 2018) for homology-based gene prediction with the alignment tool MMSeqs2 (Steinegger & Söding, 2017). As references we used the assemblies and annotations of the following ten mammals species from GenBank: Bos taurus (GCF_002263795.1), Homo sapiens (GCF_000001405.39), Mus musculus (GCF_000001635.27), Sus scrofa (GCF_000003025.6), Camelus dromedarius (GCF_000803125.2), Equus caballus (GCF_002863925.1), Ovis aries (GCF_002742125.1), Tursiops truncatus (GCF_011762595.1), Cervus hanglu yarkandensis (GCA_010411085.1), and Capra hircus (GCF_001704415.1). Subsequently, the predicted genes were annotated by a BLASTP v.2.11.0+ (Zhang et al., 2000) search against the Swiss-Prot database (release 2021-01). with an e-value cutoff of 10-6. We further annotated Gene ontology terms, motifs, and domains using InterProScan v.5.50.84 (Jones et al., 2014; Quevillon et al., 2005). The annotation results (gff3, CDS fasta, proteins fasta) can be found under the filenames: TBG_Okapi_asm_v1_annotation_all.fun.gff TBG_Okapi_asm_v1_annotation_CDS.fun.fasta TBG_Okapi_asm_v1_annotation_proteins.fun.fasta For detailed methods and additional results, please read the linked publication in the Journal of Heredity.