Will R. Shoemaker, Jay T. Lennon
Review posted on 28th June 2017
Very exciting work Will and Jay! With regards to the results depicted in Figure 4 and 5, do you see evidence that growth advantage in stationary phase (GASP) mutations are more likely to occur with increased time in seed banks? Perhaps, original GASP mutation observations were facilitated in part by such an increase in fixation rate facilitated by the methodology (Which I refer to as "SET IT AND FORGET IT!"). I have often thought about the paradox of GASP that a growing population whether it is under nutrient stress or not would benefit from some of the gain of function phenotypes that observed in GASP mutations. You can make the same mutations with targeted techniques and demonstrate increased fitness over wild-type populations. Perhaps, your models point to an explanation for the observation of GASP mutations in nutrient stressed cultures that goes beyond consideration of selective pressure, namely that while both hypothetical populations experience the same selective pressure in term of fitness gains the observation of fixation of the mutation is significantly more likely in the nutrient stressed population which may contain a significantly larger seed bank population.
It is also interesting to consider seed banks and active populations together and realize that the very existence of a large non-dividing population could make the overall population more responsive to evolution pressures and perhaps facilitate rapid expansions in functional diversity while phylogenetic diversity increases at a slower rate due to decreases in overall replications. From a metagenomic investigation stand point it will be important to be able to separate active and dormant populations. Could you start requiring your microbial populations log their active daily so we can success classify the actives and the dormants?
I am excited to see these data and models and interested in following this story as it evolves.