About a month ago I went to a talk by Princeton’s Bob Austin titled “Evolution on a Chip,” and it appears that the paper is out in this past week’s PNAS: Bacterial metapopulations in nanofabricated landscapes. The driving force behind the project, he said, was that while bacterial populations are exceptional for studying evolution and popgen in real time, chemostats are bad examples of evolution in action. Afterall, chemostats keep bacterial growth in log phase, with nutrients in excess – and as we all know, biology in the real world deals with competition for limited resources.
It’s an interesting and innovative device, and in his talk, Austin illustrated how it recapitulates the exploitation of resources, followed by population collapse, and subsequent leveling out of populations at sustainable levels. The added capacity for closely observing changes in allelic frequencies in populations makes this an exciting device for future research into the mechanisms of population change and equilibria.
The abstract is below the fold:
“We have constructed a linear array of coupled, microscale patches of habitat. When bacteria are inoculated into this habitat landscape, a metapopulation emerges. Local bacterial populations in each patch coexist and weakly couple with neighbor populations in nearby patches. These spatially distributed bacterial populations interact through local extinction and colonization processes. We have further built heterogeneous habitat landscapes to study the adaptive dynamics of the bacterial metapopulations. By patterning habitat differences across the landscape, our device physically implements an adaptive landscape. In landscapes with higher niche diversity, we observe rapid adaptation to large-scale, low-quality (high-stress) areas. Our results illustrate the potential lying at the interface between nanoscale biophysics and landscape evolutionary ecology.”
- Keymer JE, Galajda P, Muldoon C, Park S, Austin RH. Bacterial metapopulations in nanofabricated landscapes. Proc Natl Acad Sci U S A. 2006 Nov 14;103(46):17290-17295. Pubmed.