Abstract:
This study investigates the evolutionary position of the proboscis monkey (Nasalis
larvatus) within the Colobinae subfamily using in silico phylogenetic analysis of three mitochondrial
protein-coding genes (COI, COII, and COIII). Seventy sequences retrieved from GenBank were
aligned and analyzed using the Maximum Likelihood method with 1,000 bootstrap replicates. All
genes exhibited conserved lengths and strong AT bias (59,21-60,68%), reflecting typical
mitochondrial genome characteristics shaped by asymmetric replication and purifying selection.
Genetic distance analyses revealed high intraspecific consistency in Nasalis larvatus, while
demonstrating marker dependent variation in phylogenetic resolution. COII and COIII provided
clearer intergeneric separation compared to the more conserved COI marker. Phylogenetic
reconstruction showed topological variation among markers, however, a consistent evolutionary
signal emerged, with Nasalis larvatus clustering robustly with Simias concolor across all gene trees.
This pattern supports the monophyly of the odd nosed monkey clade and aligns with genome scale
phylogenomic evidence. Overall, this study highlights the limitations of single gene analyses and
emphasizes the importance of multi marker or genome scale approaches for resolving complex
evolutionary relationships. These findings provide foundational insights into the evolutionary
history of Nasalis larvatus and reinforce the relevance of mitochondrial markers in primate
conservation genetics.
