Publications by category
Journal articles
Möbius W, Tesser F, Alards KMJ, Benzi R, Nelson DR, Toschi F (In Press). The collective effect of finite-sized inhomogeneities on the spatial. spread of populations in two dimensions.
Abstract:
The collective effect of finite-sized inhomogeneities on the spatial. spread of populations in two dimensions
The dynamics of a population expanding into unoccupied habitat has been
primarily studied for situations in which growth and dispersal parameters are
uniform in space or vary in one dimension. Here we study the influence of
finite-sized individual inhomogeneities and their collective effect on front
speed if randomly placed in a two-dimensional habitat. An individual-based
model allows us to investigate the front behaviour for one or a small number of
regions in which dispersal or growth of individuals is reduced to zero
(obstacles) or increased above the background (hotspots), respectively. In a
regime in which front dynamics is determined by a local front speed,
irrespective of the microscopic origin, we (i) describe the effect of multiple
inhomogeneities in the light of an event-based solution, (ii) find a slow-down
due to obstacles that is dominated by the number density and width of
obstacles, but not by their precise shape, and (iii) characterize a speedup and
its dependence on hotspot strength and density. Our findings emphasise the
importance of taking the dimensionality of the environment into account. A
simulation-driven description of the effect of individual spatial inhomogeities
on genetic diversity of the population front provides an outlook into further
research.
Abstract.
Author URL.
Moebius W (2018). Evolution of populations expanding on curved surfaces.
EPL,
123 Full text.
Chacón JM, Möbius W, Harcombe WR (2018). The spatial and metabolic basis of colony size variation.
ISME J,
12(3), 669-680.
Abstract:
The spatial and metabolic basis of colony size variation.
Spatial structure impacts microbial growth and interactions, with ecological and evolutionary consequences. It is therefore important to quantitatively understand how spatial proximity affects interactions in different environments. We tested how proximity influences colony size when either Escherichia coli or Salmonella enterica are grown on various carbon sources. The importance of colony location changed with species and carbon source. Spatially explicit, genome-scale metabolic modeling recapitulated observed colony size variation. Competitors that determine territory size, according to Voronoi diagrams, were the most important drivers of variation in colony size. However, the relative importance of different competitors changed through time. Further, the effect of location increased when colonies took up resources quickly relative to the diffusion of limiting resources. These analyses made it apparent that the importance of location was smaller than expected for experiments with S. enterica growing on glucose. The accumulation of toxic byproducts appeared to limit the growth of large colonies and reduced variation in colony size. Our work provides an experimentally and theoretically grounded understanding of how location interacts with metabolism and diffusion to influence microbial interactions.
Abstract.
Author URL.
Weinstein BT, Lavrentovich MO, Möbius W, Murray AW, Nelson DR (2017). Genetic drift and selection in many-allele range expansions.
PLoS Computational Biology,
13(12).
Abstract:
Genetic drift and selection in many-allele range expansions
© 2017 Weinstein et al. We experimentally and numerically investigate the evolutionary dynamics of four competing strains of E. coli with differing expansion velocities in radially expanding colonies. We compare experimental measurements of the average fraction, correlation functions between strains, and the relative rates of genetic domain wall annihilations and coalescences to simulations modeling the population as a one-dimensional ring of annihilating and coalescing random walkers with deterministic biases due to selection. The simulations reveal that the evolutionary dynamics can be collapsed onto master curves governed by three essential parameters: (1) an expansion length beyond which selection dominates over genetic drift; (2) a characteristic angular correlation describing the size of genetic domains; and (3) a dimensionless constant quantifying the interplay between a colony’s curvature at the frontier and its selection length scale. We measure these parameters with a new technique that precisely measures small selective differences between spatially competing strains and show that our simulations accurately predict the dynamics without additional fitting. Our results suggest that the random walk model can act as a useful predictive tool for describing the evolutionary dynamics of range expansions composed of an arbitrary number of genotypes with different fitnesses.
Abstract.
Gralka M, Stiewe F, Farrell F, Möbius W, Waclaw B, Hallatschek O (2016). Allele surfing promotes microbial adaptation from standing variation. Ecology Letters, 19(8), 889-898.
Möbius W, Murray AW, Nelson DR (2015). How Obstacles Perturb Population Fronts and Alter Their Genetic Structure.
PLOS Computational Biology,
11(12), e1004615-e1004615.
Full text.
Möbius W, Laan L (2015). Physical and Mathematical Modeling in Experimental Papers. Cell, 163(7), 1577-1583.
Mobius W, Osberg B, Tsankov AM, Rando OJ, Gerland U (2013). Toward a unified physical model of nucleosome patterns flanking transcription start sites. Proceedings of the National Academy of Sciences, 110(14), 5719-5724.
Möbius W, Gerland U (2010). Quantitative Test of the Barrier Nucleosome Model for Statistical Positioning of Nucleosomes Up- and Downstream of Transcription Start Sites. PLoS Computational Biology, 6(8), e1000891-e1000891.
Obermayer B, Möbius W, Hallatschek O, Frey E, Kroy K (2009). Freely relaxing polymers remember how they were straightened. Physical Review E, 79(2).
Möbius W, Frey E, Gerland U (2008). Spontaneous Unknotting of a Polymer Confined in a Nanochannel. Nano Letters, 8(12), 4518-4522.
Neher RA, Möbius W, Frey E, Gerland U (2007). Optimal Flexibility for Conformational Transitions in Macromolecules. Physical Review Letters, 99(17).
Möbius W, Neher RA, Gerland U (2006). Kinetic Accessibility of Buried DNA Sites in Nucleosomes. Physical Review Letters, 97(20).
Publications by year
In Press
Möbius W, Tesser F, Alards KMJ, Benzi R, Nelson DR, Toschi F (In Press). The collective effect of finite-sized inhomogeneities on the spatial. spread of populations in two dimensions.
Abstract:
The collective effect of finite-sized inhomogeneities on the spatial. spread of populations in two dimensions
The dynamics of a population expanding into unoccupied habitat has been
primarily studied for situations in which growth and dispersal parameters are
uniform in space or vary in one dimension. Here we study the influence of
finite-sized individual inhomogeneities and their collective effect on front
speed if randomly placed in a two-dimensional habitat. An individual-based
model allows us to investigate the front behaviour for one or a small number of
regions in which dispersal or growth of individuals is reduced to zero
(obstacles) or increased above the background (hotspots), respectively. In a
regime in which front dynamics is determined by a local front speed,
irrespective of the microscopic origin, we (i) describe the effect of multiple
inhomogeneities in the light of an event-based solution, (ii) find a slow-down
due to obstacles that is dominated by the number density and width of
obstacles, but not by their precise shape, and (iii) characterize a speedup and
its dependence on hotspot strength and density. Our findings emphasise the
importance of taking the dimensionality of the environment into account. A
simulation-driven description of the effect of individual spatial inhomogeities
on genetic diversity of the population front provides an outlook into further
research.
Abstract.
Author URL.
2018
Moebius W (2018). Evolution of populations expanding on curved surfaces.
EPL,
123 Full text.
Chacón JM, Möbius W, Harcombe WR (2018). The spatial and metabolic basis of colony size variation.
ISME J,
12(3), 669-680.
Abstract:
The spatial and metabolic basis of colony size variation.
Spatial structure impacts microbial growth and interactions, with ecological and evolutionary consequences. It is therefore important to quantitatively understand how spatial proximity affects interactions in different environments. We tested how proximity influences colony size when either Escherichia coli or Salmonella enterica are grown on various carbon sources. The importance of colony location changed with species and carbon source. Spatially explicit, genome-scale metabolic modeling recapitulated observed colony size variation. Competitors that determine territory size, according to Voronoi diagrams, were the most important drivers of variation in colony size. However, the relative importance of different competitors changed through time. Further, the effect of location increased when colonies took up resources quickly relative to the diffusion of limiting resources. These analyses made it apparent that the importance of location was smaller than expected for experiments with S. enterica growing on glucose. The accumulation of toxic byproducts appeared to limit the growth of large colonies and reduced variation in colony size. Our work provides an experimentally and theoretically grounded understanding of how location interacts with metabolism and diffusion to influence microbial interactions.
Abstract.
Author URL.
2017
Weinstein BT, Lavrentovich MO, Möbius W, Murray AW, Nelson DR (2017). Genetic drift and selection in many-allele range expansions.
PLoS Computational Biology,
13(12).
Abstract:
Genetic drift and selection in many-allele range expansions
© 2017 Weinstein et al. We experimentally and numerically investigate the evolutionary dynamics of four competing strains of E. coli with differing expansion velocities in radially expanding colonies. We compare experimental measurements of the average fraction, correlation functions between strains, and the relative rates of genetic domain wall annihilations and coalescences to simulations modeling the population as a one-dimensional ring of annihilating and coalescing random walkers with deterministic biases due to selection. The simulations reveal that the evolutionary dynamics can be collapsed onto master curves governed by three essential parameters: (1) an expansion length beyond which selection dominates over genetic drift; (2) a characteristic angular correlation describing the size of genetic domains; and (3) a dimensionless constant quantifying the interplay between a colony’s curvature at the frontier and its selection length scale. We measure these parameters with a new technique that precisely measures small selective differences between spatially competing strains and show that our simulations accurately predict the dynamics without additional fitting. Our results suggest that the random walk model can act as a useful predictive tool for describing the evolutionary dynamics of range expansions composed of an arbitrary number of genotypes with different fitnesses.
Abstract.
2016
Gralka M, Stiewe F, Farrell F, Möbius W, Waclaw B, Hallatschek O (2016). Allele surfing promotes microbial adaptation from standing variation. Ecology Letters, 19(8), 889-898.
2015
Möbius W, Murray AW, Nelson DR (2015). How Obstacles Perturb Population Fronts and Alter Their Genetic Structure.
PLOS Computational Biology,
11(12), e1004615-e1004615.
Full text.
Möbius W, Laan L (2015). Physical and Mathematical Modeling in Experimental Papers. Cell, 163(7), 1577-1583.
2013
Mobius W, Osberg B, Tsankov AM, Rando OJ, Gerland U (2013). Toward a unified physical model of nucleosome patterns flanking transcription start sites. Proceedings of the National Academy of Sciences, 110(14), 5719-5724.
2010
Möbius W, Gerland U (2010). Quantitative Test of the Barrier Nucleosome Model for Statistical Positioning of Nucleosomes Up- and Downstream of Transcription Start Sites. PLoS Computational Biology, 6(8), e1000891-e1000891.
2009
Obermayer B, Möbius W, Hallatschek O, Frey E, Kroy K (2009). Freely relaxing polymers remember how they were straightened. Physical Review E, 79(2).
2008
Möbius W, Frey E, Gerland U (2008). Spontaneous Unknotting of a Polymer Confined in a Nanochannel. Nano Letters, 8(12), 4518-4522.
2007
Neher RA, Möbius W, Frey E, Gerland U (2007). Optimal Flexibility for Conformational Transitions in Macromolecules. Physical Review Letters, 99(17).
2006
Möbius W, Neher RA, Gerland U (2006). Kinetic Accessibility of Buried DNA Sites in Nucleosomes. Physical Review Letters, 97(20).