Exploring Hidden Genetic Divergence Within Sunda Colugos by Means of Novel DNA Capture Methods and Next Generation Sequencing

Abstract

It has been the goal of biologists to catalog and protect genetic diversity and variation among biological organisms. The amount of diversity cataloged is growing every year. In the twelve years between the latest two publications of Mammal Species of the World, the number of mammalian species increased from 4998 to 5339 (~7%). This number is expected to increase substantially, especially with the advent and application of new genomic approaches to assess levels of species diversity. This increased diversity is partially due to increased taxonomic investigation in Southeast Asia, which is known for being a hot spot of species richness. This richness has been shown in recent years to be continually threatened by human induced habitat loss, as is the case of a poorly known group of mammals, the flying lemurs, or colugos. The colugo is a small arboreal mammal that inhabits more than fifty islands in the SE Asian archipelago and adjacent mainland areas of the Malay Peninsula, Thailand and Vietnam. The colugo has extremely inefficient terrestrial locomotor capabilities, which isolate the colugo to forested areas, where it is capable of gliding over one hundred meters between trees. This study proposes a molecular phylogenetic analysis of the Sunda colugo (Galeopterus variegatus) to redefine the evolutionary relationships between disjunct populations of this poorly understood mammal, using a novel DNA capture method to isolate degraded mtDNA fragments from museum samples, by hybridization to DNA fragments derived from a modern colugo genome. The results demonstrate extremely efficient crossspecies capture of mtDNA sequences as great as 10-15% divergent from the probe, combined with Next Generation Sequencing Technologies to obtain high depth of coverage of hybridized sequences. Phylogenetic results indicate the widespread presence of species-level taxonomic units both within and between the islands of the Southeast Asian archipelago. This novel approach to ancient DNA capture has potentially broad implications for the conservation of this enigmatic mammal, and further suggest that vicariant evolutionary analysis of colugos will be invaluable for defining the biogeographic history of the SE Asian archipelago.