30 The incidence rate of KRAS mutations is fairly consistent across several studies, and a similar incidence rate has been reported both in early-stage and metastatic disease.
Since the discovery of these ultrarare mutations is fairly recent, there have not been any published studies thus far examining their functional effects.
Mutations are fairly common but normally our DNA-repair mechanisms keep them from causing disease.
Further, they also showed that inactivating deletions or point mutations are fairly common in the FOXP3 gene in human prostate cancers and PIN lesions [86], and that FOXP3 can directly repress MYC mRNA levels.
First, heterozygous mutations are fairly common in healthy subjects [13], and second, the presence of an apparent single heterozygous mutation in a PD patient typically should not rule out PRKN as the causative gene, since other unscreened mutations may be present [16].
For mitochondrial DNA control region, the substitution rate has been estimated as 7.1 × 10−8 per site per year (Barluenga and Meyer 2004), which, despite the fact that control region should have a high mutation rate, is fairly well in agreement with our current genome-wide mutation rate estimate.
Indeed, only if the per-locus mutation rate is fairly large (θ > 0.1 ), does the shape of the distribution of allele frequencies become important, and the increase in P SGV with θ becomes less than linear).
It suggests that populations may be able to adapt to quite rapid deterioration, provided that the mutation supply rate is fairly large.
Third, mapping the mutations induced by EMS is fairly challenging since the mutated loci are not tagged with recognizable sequences, unlike some other approaches such as P-element-mediated disruptions (the details will be discussed later).
This is fairly consistent with mutation rate estimates for Caenorhabditis elegans and Drosophila: 2.1×10-8 and 0.8×10-8 per site per generation, respectively (reviewed in [ 65]).
