Hence, the phenotypic fluctuation (variance) increases with a decrease in robustness, and vice versa.
As the noise level reduces resulting in a decrease in robustness, the fraction of genes sharing a common value of V g(i) /V ip(i) = ρ decreases.
But unlike the K1 models where variation of Sig + kinases' concentration resulted in two fold decrease in robustness as compared to kinases' concentration variation with constant Sig (Compare Figure 2A and 2C), the K2 models showed very little change in MK-PP robustness while subjected to such perturbations (Compare Figure 3A and 3C; Figure 3B and 3D).
We conclude that during early stages of cellular transformation, cells gain higher proliferation rate, which occurs concurrently with higher activation of p53 and a decrease in cell robustness.
This small decrease in the robustness of the statistical results with respect to the first experiment, where only 1.5% of all comparisons showed an uncorrected p-value below.05, is likely due to the less optimal procedure employed to estimate the transient templates in Experiment 2. The scalp topographies for both recorded and synthetic data are shown in Figure 8.
Using this measure, we found that removing positive feedback leads to a decrease in phase robustness and that this is a consequence of a transition from systematic to dusk-driven entrainment in long days.
Price et al. (2011) have already dealt with this situation and have shown, on average, a small, yet marginally significant, decrease in mutational robustness and a likewise small increase in plasticity for Drosophila pre-miRNAs over millions of years of evolution.
The analysis above suggests that the decrease in the robustness of FRQ-dependent entrained phase ϕ FRQ observed on decoupling the wc-1 loop is related to a loss of flexibility, since for the decoupled system, ϕ FRQ no longer responds to dawn changes in long days.
Several groups noticed another side effect, a general decrease in animal robustness, when treatment with rapamycin was started in very young mice [ 1, 8]; this underscores the importance of mTOR pathway activity during development and points out to the significance of another variable, the onset of treatment, in diminishing of side effects.
For all 14 models a decrease in p reduces robustness of both singular variables, defined as the minima of CV1 k and CV2 k over all 81 parameter sets (Fig. 5).
In contrast, disturbed forest will show the opposite effect: increased network size results in decreased NODF and connectance, which in turn result in decreased robustness.
