09/15/2016 — Welcome to the new postdocs Marie-Cecilia Duvernoy, Jayson Paulose, and Miller fellow Ben Good!
08/12/2016 — Congratulations to Diana for being selected as a participant in the Rising Stars in Physics workshop at MIT this coming October!
08/01/2016 — Check out Oskar‘s talk “On the statistics and control of drug resistance evolution from pre-existing mutations” given at the Stochastic and Deterministic Models for Evolutionary Biology symposium in Oaxaca, Mexico.
07/26/2016 — Our paper “Excess of mutational jackpot events in expanding populations revealed by spatial Luria-Delbrück experiments” has been accepted in Nature Communications (preprint: http://dx.doi.org/10.1101/053405). In this paper, we track large mutational clones (“jackpot events”) in microbial populations using fluorescent microscopy and population sequencing. High-frequency mutations are massively enriched in microbial colonies compared to well-shaken liquid cultures, as a result of late-occurring mutations surfing at the edge of range expansions. We provide a mathematical theory that explains the observed excess of jackpot events and predicts their role in promoting rare evolutionary outcomes. In particular, we show that resistant clones generated by surfing can become unleashed under high selection pressures, and thus represent a drug resistance hazard for high-dose drug treatments. An excess of mutational jackpot events is shown to be a general consequence of non-uniform growth and, therefore, could be relevant to the mutational load of developing biofilm communities, solid tumors and multi-cellular organisms.
07/15/2016 — Our commentary “Watching Populations Melt Down” has been published in Biophysical Journal (dx.doi.org/10.1016/j.bpj.2016.06.020, pdf)! In this paper, we discuss the recent study “Spatially Constrained Growth Enhances Conversional Meltdown” (dx.doi.org/10.1016/j.bpj.2016.05.024), especially its really cool experimental set-up and its historical context of mutational meltdown, error catastrophe and Muller’s ratchet.
06/16/2016 — Our paper “Allele surfing promotes microbial adaptation from standing variation” has been published in Ecology Letters (dx.doi.org/10.1111/ele.12625, pdf)! In this paper, we show how due to the coupling of ecology and evolution during range expansions, they generate a larger increase in mean fitness than spatially uniform population expansions. The adaptation gain results from ‘soft’ selective sweeps emerging from surfing beneficial mutations. The rate of these surfing events is shown to sensitively depend on the strength of genetic drift, which varies among strains and environmental conditions. Check out some more details here.
05/09/2016 — Our paper “Self-driven jamming in growing microbial populations” has been published in Nature Physics (dx.doi.org/10.1038/nphys3741). In this paper, we reveal a collective mechanism of confinement, which we call self-driven jamming, that promotes the build-up of large mechanical pressures in microbial populations. These pressures can become large enough to slow down cell growth, to delay the cell cycle in the G1 phase, and to strain or even destroy the micro-environment through crack propagation. Our results suggest that self-driven jamming and build-up of large mechanical pressures is a natural tendency of microbes growing in confined spaces, contributing to microbial pathogenesis and biofouling. Check out some more details here.
05/01/2016 — Congratulations to Jona who was awarded the prestigious German Research Foundation (DFG) fellowship!