Wright-Fisher Model
The Wright-fisher model for genetic drift that provides powerful insights into population genetic dynamics. The model is not popular because is build with very specific assumptions that are not often satisfied. This assumptions are a fixed population size, there is no selection, no mutation, no migration and non-overlapping generation times and diploid populations.
In the study presented in \citep{Ilhan_2018} they apply a standard haploid version of the Wright-Fisher model to simulate the evolution of a population that is subject to random genetic drift \citep{guillespie2010}. To incorporate plasmids evolution they followed the approach used in \citep{Peng_2005} a study of mitochondrial evolution. With this framework they study plasmid segregational drift, a process well described in mitochondria but never studied before in plasmids. Using both modeling and experimental approaches they compared the relation between plasmid copy number and mutations (or allele variants) drift. Comparing populations with different plasmid copy numbers and chromosomal alleles (population sizes adjusted). They conclude that plasmid occurring mutations are easily lost by segregational drift and that the allele frequency of mutation residing on plasmids is increasing slower in comparison to chromosomal alleles.