Background: Pangolins are critically endangered mammals, and a comprehensive understanding of their genetic diversity is crucial for effective conservation. The mitochondrial genome serves as a vital molecular marker for phylogenetic and population genetic studies. Obtaining genetic material from these elusive animals non-invasively remains a challenge. This study aimed to sequence and characterize the complete mitochondrial genome of Manis javanica and explore the phylogenetic relationships among pangolin species. Methods: The complete mitochondrial genome was sequenced from a saliva-derived sample. Standard procedures for DNA extraction, amplification, and sequencing were employed. The genome was assembled and annotated using bioinformatic tools. Phylogenetic analysis was conducted based on the cytochrome c oxidase subunit I (COXI) gene sequences from nine pangolin species, with the resulting tree constructed using the maximum-likelihood method. Results: The complete mitochondrial genome of M. javanica (GenBank accession: PP110760) is a circular molecule of 16,573 bp, containing 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a control region. The overall base composition showed a lower GC content (43.83%) than AT content (56.17%). Phylogenetic analysis based on COXI sequences delineated the nine species into three distinct genera: Manis, Phataginus, and Smutsia. Within the genus Manis, Manis pentadactyla was identified as the closest relative to M. javanica. The newly described species Manis mysteria was found to be closer to Manis culionensis and Manis crassicaudata than to other congeners. Furthermore, the analysis indicated that African pangolins diverged earlier than Asian pangolins. Conclusions: This study successfully demonstrates the feasibility of extracting and sequencing the complete mitochondrial genome from saliva samples, providing a valuable non-invasive method for future genetic studies on pangolins. The genomic data and phylogenetic results offer significant molecular insights that will benefit the genetic management and conservation of critically endangered pangolin resources.
Guo et al. (Thu,) studied this question.