The threshold calculations based on nuclear DNA control libraries demonstrated that the average proportion of mutations per base was 0.06 % and no base was mutated at greater than 0.8%% frequency (He et al. 2010).
c The smaller the mutational step relative to the curvature (i.e. distance from the optimum), the greater will be the proportion of mutations that are advantageous.
Patients with the mental illness, which affects about one in every 100 people, had a higher proportion of mutations known as copy number variations in the genes involved with exciting or inhibiting the synapses between brain cells, the researchers report.
The observed fluctuations in heteroplasmy levels could be due to the different reprogramming states of the cell lines, i.e., highly pluripotent iPSCs predominantly produce energy by anaerobic glycolysis and carry a high proportion of mutations, even above the pathogenic threshold level.
However, if the sites being considered are subject to selection then the proportion of mutations that are effectively neutral will depend directly on the effective population size.
However, irrespective of this limitation, it does appear that the proportion of mutations associated with T-cell pressure is higher in HIV (30 60%) than for HCV (31.8%).
As the population size increases so the level of neutral diversity increases, but at the same time the proportion of mutations that are effectively neutral decreases.
Previous studies examining viral evolution during acute and early HCV infection on a small number of subjects showed that the proportion of mutations likely to be associated with CD8+ T-cell immune pressure varies from 11 25% [9], [13].
There are two general explanations; first, the proportion of mutations that are strongly deleterious is higher in 18S rDNA, when compared to protein sequences, in unicells compared to multicells.
A large proportion of mutations presumably result in functional haploinsufficiency for RPS19 by removing transcription from one allele (deletions or insertions) or by nonsense mediated mRNA decay (splice site, non-sense and missense mutations) [4].
As shown in Figure 2, we observed that in the hypermutator isolates, the proportion of mutations that occurred in the mexZ and mucA genes was not significantly different to that observed in the nonmutator isolates (P = 0.17 and P = 1.00 respectively).
