The whole genome sequence and assembly of the Southern Ground Hornbill (Bucorvus leadbeateri).

Patel, J.*, Mollett, J., De Maayer, P.

University of the Witwatersrand, 1 Jan Smuts Avenue, Johannesburg, 2050, Gauteng, South Africa

The Southern Ground Hornbill (SGH), scientifically known as Bucorvus leadbeateri, holds a prominent position as the flagship species of the African savannah biome. However, this majestic bird faces critical challenges, including declining population numbers and disappearance from its historical ranges across southern Africa. While significant knowledge exists regarding the SGH’s survival strategies, lifestyle, and behavioral patterns, its genetic potential remains largely unexplored. This study presents the first sequenced, de novo assembled and annotated genome of the SGH using a combination of long- and short-read sequencing technologies. A 1.16 Gb high-quality draft SGH genome assembly comprised of 1,672 contigs (N50 value of 40.45 Mb) and G+C content of 43.50% was obtained from a refined hybrid de novo assembly. This genome provided a basis for comparative genomic analysis of the SGH against available hornbill genomes which included the Abyssinian Ground Hornbill (AGH – Bucorvus abyssinicus). Notably, our comparative analysis revealed 51,779 genetic variants with significant impact on protein-coding sequences, distinguishing the SGH and AGH genomes. Some of these variants are predicted to play essential roles in immune responses via the MHC class II antigens. Furthermore, the observed genetic diversity between the SGH and AGH may confer selective advantages, aiding their adaptation to distinct habitats across Africa. Ultimately, this study provides a pivotal platform for large-scale population genetic analyses of the SGH which will aid in conservation efforts aimed at safeguarding the remaining population of these remarkable birds.

Keywords: whole genome sequencing, de novo assembly, comparative genomics and conservation