Resolving repetitive and telomeric regions through a high-contiguity genome assembly of the African Turquoise killifish.

BACKGROUND: The turquoise killifish (Nothobranchius furzeri) is a powerful, short-lived vertebrate model for aging and evolutionary biology, characterized by rapid growth, high fecundity, and a distinctive life cycle. However, the existing reference genome has limitations in accurately resolving repetitive genomic regions and telomeric sequences. OBJECTIVE: In this study, we present a high-quality genome assembly of the GRZ strain of the turquoise killifish (Nothobranchius furzeri), generated using high-fidelity long-read sequencing to provide a robust genomic resource for aging research. We assessed the assembly quality with a focus on repetitive elements, particularly the resolution of telomeric regions, as well as evolutionarily conserved genes and overall gene content. METHODS: We obtained high-fidelity (HiFi) long-read sequencing data using the PacBio Sequel2 platform to assemble the genome. To identify and remove contaminant sequences, taxonomic classification of scaffolds was performed. Genes of the genome were annotated with publicly available RNA sequencing data. RESULTS: Compared with the previously published reference (MPIA_NFZ_2.0), the current assembly showed markedly higher contiguity and improved resolution of repetitive sequences. These findings indicate that the larger genome size is largely attributable to the more complete representation of repetitive sequences. Notably, the recovery of the majority of telomeric sequences demonstrates a substantial advance in assembly completeness. CONCLUSION: This enhanced genome assembly provides a critical resource for advancing research on aging using the turquoise killifish model. The resulting high-contiguity genome assembly establishes a valuable reference resource that will accelerate genetic and genomic studies and enable deeper insights into phenotypic evolution in this species.