Decomposed cadaver tissue provides insight into genetic variation in a freshwater turtle (Chelodina oblonga Gray, 1841) population at Bibra Lake, south-western Australia

Context Obtaining a source of genetic data is a key constraint in population genomic research. Aims In this study, single-nucleotide polymorphisms (SNPs) were generated from oblong turtle (Chelodina oblonga) cadavers, to ascertain whether decomposed tissue could be used as a source of genetic data and to investigate genetic variation. Methods Tissue was opportunistically collected from 47 cadavers following a mass mortality event during April 2024 at Bibra Lake, Western Australia. Genotyping was performed using a Chelodina DArTseq platform, with a high-density assay of 2.5 million sequence reads. Key results Genetic diversity and inbreeding were investigated for 39 individual C. oblonga, using 8053 SNPs retained from data filtering. Observed and expected heterozygosities (HO = 0.26, HE = 0.31) for C. oblonga were relatively low compared with other freshwater turtle species within Australia. A high inbreeding coefficient (FIS = 0.17) was also detected, suggesting that inbreeding may threaten C. oblonga population viability at Bibra Lake. Conclusions This study highlights the utility of decomposed turtle cadavers as a viable source of DNA. Implications Management plans should implement strategies to improve gene flow between Bibra Lake and adjacent populations, such as establishing wildlife corridors to encourage migration between populations.