PLASMIDOME COMPOSITION IS GOVERNED BY STOCHASTIC DISPERSAL WHILE ITS FUNCTIONALITY IS DICTATED BY ECOSYSTEM STATE AND GEOGRAPHY

Plasmids are self-replicating, extrachromosomal genetic entities. They can serve as mediators of horizontal gene transfer, a process considered to be a strong determinant in the evolution of microbial communities. The mobile fraction of the plasmidome (the overall plasmid population) can mobilize between different host cells, which can be different species. In nature, plasmids often encode genes that benefit their carriers. Here we assess the functional and ecological behavior of plasmidomes from the bovine rumen and the human gut. We find different functional profiles that are associated with plasmid mobility and ecosystem state, functionality which are such as disease states of Crohn`s disease and ulcerative colitis as well as geographic origin of the mammalian host. Most interestingly, the dispersal of mobile plasmids into different gut ecosystems shows signs of a stochastic process that can be explained by a neutral ecological model, whereas the non-transmissible fraction shows a higher contribution of natural selection.