A pinboard by
Timothy Colston

Postdoctoral Researcher, The George Washington University


I study how micro-organisms living in and on reptiles influence host ecology and evolution.

Vertebrates are metagenomic organisms; they are not only composed not only of their own genetic material, but also that of their associated microbial communities. The majority of these microorganisms are found in the host’s intestinal tract and presumably assist in essential processes of energy and nutrient acquisition. The ecological and evolutionary forces that act on both the host and it’s trillions of resident microorganisms sculpt the endogenous (gut) microbiome. With the advent of next generation sequencing technologies we are now better able to characterize and explore factors that gave rise to this observed microbial diversity. Most studies investigating evolutionary patterns in non-human vertebrate endogenous microbiomes have focused on captive animals from zoos rather than wild populations. Very few studies have examined the gut microbiome of squamate reptiles (snakes, lizards), despite this being one of the most diverse and successful vertebrate clades. I explored and characterized the gut microbial communities across Squamata. Using metagenomic scans of the bacterial 16S rRNA gene and next generation sequencing I showed that the reptile gut microbiome is highly conserved across squamates, and is more similar to avian reptiles (birds) than carnivorous mammals as previously hypothesized. Lizards have distinct microbiomes when compared to snakes, showing phylogenetic constrains on the microbiome, while ecology and life history (e.g. foraging & parity mode) are significantly correlated with shifts in gut microbial community structure. I am now exploring the functional role of these microbiome in response to emergent diseases, and am attempting to understand how reptiles acquire their endogenous microbiomes.