Models to examine containment and spread of genetically engineered microbes


  • This work is the result of inter disciplinary collaboration between two mathematicians (Mark Lewis and Greg Schmitz), a theoretical ecologist (Peter Kareiva) and a microbial ecologist (Jack Trevon), aiming to understand the fundamental processes that control the spread of GEMs in a field setting. The study was initiated when Mark Lewis was a postdoctoral research fellow working with Peter Kareiva at the University of Washington. A key interest of Mark Lewis is the realistic modelling of movement and spatial spread of organisms. Under his supervision graduate student Greg Wmitz developed and analysed a model for GEM growth, competition and movement. Peter Kareiva's research involves a mix of theory and field experiment in the modellingspatial processes in ecology. Jack Trevon research includes environmental risk assessment for GEMs and the survival, respiration and movement of GEMS in soil.

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Genetically engineered microbes (GEMs) have the potential to revolutionize agricultural techniques by facilitating crop protection and increased productivity. However, there has been widespread concern regarding the potential impact these microbes may have on the environment. Here we mathematically model the dynamics of GEMs in an agricultural setting, focusing on parameters that can be used to summarize the potential of modified microbes for persistence and spread. First developing a comprehensive model for the dynamics of GEMs which includes mobile and stationary classes of GEMs as well as competition from indigenous microflora, we then analyse a sequence of simplified mathematical models with a view to answering two fundamental questions: (1) will the GEMs spread (or invade), and if so how quickly? and (2) what are the best strategies for containing the spread of GEMs in a spatially varying environment?