JC virus genotype profile in the Mamanwa, a Philippine Negrito tribe, and implications for its population history

Abstract

JC virus (JCV) is ubiquitous in the human population, usually being transmitted from parents to children during cohabitation. JCV genotyping is a useful means of elucidating the origins of various ethnic groups in the world. We used this method to gain insights into the origin of the Mamanwa, a Philippine Negrito tribe in Northeast Mindanao. We found that the Mamanwa carried two major JCV genotypes, B3-b/2E and SC-f/7A. This was in contrast with the JCV genotype profile of modern Filipinos who carry up to five genotypes, with B3-b/2E showing only a low frequency. B3-b/2E is spread throughout Oceania but rare on the Asian continent. In contrast, SC-f/7A is spread throughout Southeast Asia (including neighboring Oceanic islands) but rare in Remote Oceania. The present findings thus suggest that the Mamanwa tribe was formed by early colonization by people carrying B3-b/2E followed by an admixture of more recent immigrants carrying SC-f/7A. As the indigenous tribe (the Chamorro) in the Mariana Islands has essentially the same JCV genotype profile as the Mamanwa, other indigenous tribes in Southeast Asian and Oceanic islands may have a population history analogous to that suggested for the Mamanwa.