Evolutionary history of orangutan plasmodia revealed by phylogenetic analysis of complete mtDNA genomes and new biogeographical divergence dating calibration models

Abstract

During the past 15 years, researchers have shown a renewed interest in the study of the Plasmodium parasites that infect orangutans. Most recently, studies examined the phylogenetic relationships and divergence dates of these parasites in orangutans using complete mitochondrial DNA genomes. Questions regarding the dating of these parasites, however, remain. In the present study, we provide a new calibration model for dating the origins of Plasmodium parasites in orangutans using a modified date range for the origin of macaques in Asia. Our Bayesian phylogenetic analyses of complete Plasmodium sp. mitochondrial DNA genomes inferred two clades of plasmodia in orangutans (Pongo 1 and Pongo 2), and that these clades likely represent the previously identified species Plasmodium pitheci and Plasmodium silvaticum. However, we cannot identify which Pongo clade is representative of the morphologically described species. The most recent common ancestor of both Pongo sp. plasmodia, Plasmodium. hylobati, and Plasmodium. inui dates to 3–3.16 million years ago (mya) (95% highest posterior density [HPD]: 2.09–4.08 mya). The Pongo 1 parasite diversified 0.33–0.36 mya (95% HPD: 0.12–0.63), while the Pongo 2 parasite diversified 1.15–1.22 mya (95% HPD: 0.63–1.82 mya). It now seems likely that the monkey Plasmodium (P. inui) is the result of a host switch event from the Pongo 2 parasite to sympatric monkeys, or P. hylobati. Our new estimates for the divergence of orangutan malaria parasites, and subsequent diversification, are all several hundred thousand years later than previous Bayesian estimates.

Primatology and one health: Two disciplines destined to come together

“…Unwin and colleagues (2021) look at the work of the Orangutan Veterinary Advisory Group using semi‐ quantitative data to build capacity among people working with orangutans to improve both conservation medicine and clinical veterinary skills among its members. Reid and colleagues (2021) provide us with a new model looking at the evolution of orangutan malaria causing parasites. They argue that there are two different orangutan malaria parasites and that these parasites are quite old, with one arising as early as 1.8 million years ago and the other arising between 630 and 120 thousand years ago, while sharing close evolutionary relationships with leaf monkey, gibbon and human malaria parasites.…”