(Neutral) Range Expansion

red ballRange Expansion: Bacteria reproduce and compete for new space

yellow ball"Genetic drift at expanding frontiers promotes gene segregation,"

O. Hallatschek, P. Hersen, S. Ramanathan, & D.R. Nelson, PNAS 104, 19926 (2007).

yellow ball Range expansion can also be initiated on a straight edge:

red ball Stepping Stone models for (neutral) range expansion:

yellow ball"Genetic demixing and evolution in linear stepping stone models,"

K.S. Korolev, M. Avlund, O. Hallatschek & D.R. Nelson, Rev. Mod. Phys.82, 1691 (2010).

yellow ball Layer by layer (synchronous-flat growth):                          

 

red ball Synchronous growth model predicts diffusive sector boundaries, but in experiments sector boundaries fluctuate super-diffusively

  

yellow ballRemove the layer by layer growth constraint to allow for rough fronts: