DNA barcoding of primates and the selection of molecular markers using African Great Apes as a model

Ambiguities within species description and identification may compromise research validity. Species identification has typically been based upon morphological characteristics, yet recent technological advances have led to identifications achieved via DNA approaches, including DNA barcoding. DNA barcoding studies typically use cytochrome c oxidase subunit I (COI) as the proposed universal molecular marker for animals. Here, we test 12 mitochondrial protein coding genes for the presence of a clear barcoding gap allowing us to unequivocally define species. Using the African Great Apes as our model group, we assess this at the species (Pan troglodytes), genus (Pan) and family (Hominidae) level. Based on 279 complete mitochondrial genomes, sequences were partitioned by gene for analysis and pairwise distances were calculated. No barcoding gap was observed at the within species level, i.e., the four recognised chimpanzee taxa were not distinguishable through DNA barcoding. However, NADH dehydrogenase subunit 5 (ND5) and cytochrome c oxidase subunit II (COII) produce the largest barcoding gaps at the genus (ND5 2%, COII 0.5%) and family (ND5 1.5%, COII 0.5%) level. Rather than focusing on COI, our analysis suggests that these two genes may be more, or at least as, appropriate markers in primate species delineation, with uses in the identification of extinct and extant species. Further use may be beneficial to taxonomists, providing additional evidence and new insights for these morphologically similar species.