Optimal segregation of key proteins in microbes

Asymmetric segregation of key proteins at cell division has been observed in various unicellular organisms, including E. coli and budding yeast. It is often assumed to enhance the fitness of the population. We study the population growth in the presence of asymmetric segregation and find, generically, a phase transition occurring between a regime where asymmetry is beneficial to one where it is detrimental. We investigate the nature of this phase transition in the presence of asymmetry in cell division, stochasticity and multiple key proteins, each of which can be beneficial or deleterious, segregating in different proportions.