a small chemostat. The above points are expected to be the same across different asexually reproductive species (E. coli, S. cerevisiae, etc.). Furthermore, the time until mutation appearance is independent of genome size, but dependent on per-BP mutation rate. For characteristically large chemostats, a hyper-mutating strain does not give enough of an advantage to warrant use. Also, it does not have enough of a selective advantage to be expected to always appear through random mutation and take over the chemostat. Single takeover The takeover time is predictable given the relevant strain parameters. Different dilution rates selectively favor different mutant strains to take over the chemostat population, if such a strain exists. For example: A fast dilution rate creates a selection pressure for a mutant strain with a raised maximal growth rate; A mid-range dilution rate creates a selection pressure for a mutant strain with a higher affinity to the limiting substrate; A slow dilution rate creates a selection pressure for a mutant strain which can grow in media with no limiting substrate (presumably by consuming a different substrate present in the media); The time for takeover of a superior mutant will be quite constant across a range of operation parameters. For characteristic operation values the take over time is on the order of days to weeks. Successive takeovers When the conditions are right (a large enough population, and multiple targets in the genome for simple advantageous mutations) multiple strains are expected to successively takeover the population, and to do so in a relatively timed and paced manner. The timing depends on the type of mutations. In a takeover succession, even if the selective improvement of each of the strains stays constant (e.g. each new strain is better than the previous strain by a constant factor) – the takeover rate does not stay constant, but rather diminishes from strain to strain. There are cases where successive takeovers occur so rapidly that it is very difficult to differentiate between strains, even when examining allele frequency. Thus, a lineage of multiple takeovers of consecutive strains might appear as the takeover of a single strain with a cohort of mutations. Variations Fermentation setups closely related to the chemostats are the turbidostat, the auxostat and the retentostat. In retentostats, culture liquid is also removed from the bioreactor, but a filter retains the biomass. In this case, the biomass concentration increases until the nutrient requirement for