Metamobilomes: The Plasmid Metagenome of Natural Environments

Abstract

Synopsis The horizontal gene pool is the collection of genes on mobile elements that are distributed across potentially connected microbes and can be accessed by those microbes via horizontal transfer. Characterization of the pool is limited by the fact that any microbes from a range of environments are unculturable, so to determine what plasmids and associated genes they carry can be difficult. The plasmid metagenome can be accessed by pooling bacteria and extracting plasmid DNA without going through a cultivation stage followed by a variety of amplification steps before sequencing. Technically, it is difficult to avoid biasing the library of fragments sequenced, particularly in favor of smaller plasmids, and the field is still searching for the best solutions. Nevertheless, the glimpses of metamobilomes already available are encouraging and, coupled with synthetic biology to test the properties of elements first discovered in silico, provide a justification for major effort in this field.