An assessment of South African small mammal barcode sequence libraries: Implications for future carnivore diet analyses by DNA

DNA metabarcoding requires reference libraries that link DNA sequences to species. Mitochondrial gene regions cytochrome c oxidase I (COI), 12S ribosomal RNA (12S rRNA), 16S ribosomal RNA (16S rRNA), cytochrome b (cyt b) and the hypervariable control region (D-loop) are routinely used in studies that measure genetic diversity in animal species. This study aimed to review the state of DNA reference libraries for small South African mammals as small mammals constitute a large portion of small and medium carnivore diet. Analyses of DNA records revealed that of 193 small mammal species in South Africa, only 141 have DNA sequences available for one or more of the mitochondrial genes examined. Cyt b had the highest species coverage, with 59.1% of South African species represented in the reference libraries. COI only has 33.7%, 12S rRNA has 23.8%, D-loop has 17.6%, and 16S rRNA has the lowest species coverage of 15%. This study supports the use of multiple gene regions when performing scat metabarcoding, particularly when wanting to determine the small mammal component of the diet. Additionally, it emphasises the need to build comprehensive DNA reference libraries linking sequences to taxonomically identified species.