The nested regions model incorporates this increase in genetic drift during the geographic expansion through increased bottleneck severity between regions relative to bottleneck severity within regions.
Because of the increased bottleneck severity between regions, unlike the modern serial founder model, the nested regions model also reproduces the larger differences in values of the three summary statistics observed between regions compared to values observed within regions.
Several states are expecting a higher than usual turnout, which could increase bottlenecks in precincts with too few voting machines.
It was hypothesised that the frequency of evolved SM cheats would increase with increasing bottleneck size.
In line with predictions, the frequency of evolved cheats within the populations increased with increasing bottleneck size.
As predicted, the frequency of evolved SM cheats inhabiting the biofilm increased with increasing bottleneck size (Figure 1, Table 1; F1,19 = 5.72, P = 0.027), suggesting that reductions in relatedness caused by larger bottlenecks disfavoured cooperation.
We therefore propose that upregulating mitophagy may be a fruitful pathway of investigation for increasing bottlenecking power, either as a standalone effect or due to the action of compensatory mechanisms it may invoke.
This view is supported by a recent report showing that the fitness of an invasive species of ladybirds is actually increased by bottlenecks having resulted in a decrease of their mutation load [ 63].
This is consistent with studies showing diminished genetic variability in natural populations resulting in increased genetic bottlenecks, inbreeding, reductions in effective population size and the potential for reduced adaptability and productivity (Hauser et al. 2002; O'Leary et al. 2013).
Thus, Figure 2C shows that decreasing the severity of the bottleneck by increasing the bottleneck population size reduces the probability that the lineages coalesce during the most recent bottleneck.
