(Neutral) Range Expansion


red ballRange Expansion: Bacteria reproduce and compete for new space

yellow ball"Genetic drift at expanding frontiers promotes gene segregation," Hallatschek, Hersen, Ramanathan, & Nelson, PNAS 104, 19926 (2007).

yellow ball The boundaries between domains fluctuate `super-diffusively'

red ball Sector boundaries: Asynchronous stepping Stone models for neutral range expansion justify scaling reminiscent of other growth processes

yellow ball"Genetic demixing and evolution in linear stepping stone models," Korolev, Avlund, Hallatschek & Nelson, Rev. Mod. Phys.82, 1691 (2010).

red ball Neutral growth on a sloped surface:

yellow ball Sector boundaries drift on a sloped surfaces, as

yellow ball Stochastic fluctuations in height profile of the rough surface thus lead to random drift of the sector boundary, such that

yellow ball Variations of the height profile (hence slope) are due to the random additions, which are described by

yellow ballThe generic scaling of fluctuations of the above equation is super-diffusive: