Evolutionary, chromatin structure may influence the distribution of point mutations or other mutational events in the promoter sequence.
The MECP2 gene has some unique characteristics: (1) it is mainly affected by de novo mutations, due to recurrent independent mutational events in a defined "hot spot" regions or positions; (2) complex mutational events along a single allele are frequently found in this gene; (3) most mutations arise on paternal X chromosome.
If one assumes a constant mutation rate per cell division, mutational events in a cell population follow poisson statistics.
In addition, this finding suggests that genetic lineage and point mutation may be moderators of mutational events in those alleles with nine repeat motifs.
Likewise, it is unclear whether these mutations represent remnants of early mutational events in tumors or stem from certain niches of it.
The c.68_69delAG mutation has also been found in the non-Ashkenazi-Jewish, Spanish and UK (Yorkshire) populations, with haplotype evidence for this mutation having arisen by independent mutational events in different populations (Neuhausen et al, 1996; Fackenthal and Olopade, 2007).
Available data suggest that the most frequent mutational events in these carcinomas are mutations in B-RAF, leading to activation of the RAF/MEK (mitogen-activated protein/extracellular signal-regulated kinase (ERK) kinase)/ERK pathway and in phosphoinositide 3-kinase (PI3K /AKT signalling (Kimura et al. 2003, Hou et al. 2007).
We observed more than two mutations in the A-1 F1 and D-1 F1 worms, suggesting multiple mutational events in these animals, most likely in both the germ cells and somatic cells.
Based on this fact, we have developed a computational scheme for inference of point mutational events in human segmental duplications, which we collectively term duplication-inferred mutations (DIMs).
These types of mutations, i.e. C or mC to T mutations at 5′TC, 5′CC, 5′TmC, and 5′CmC, are recognized as the major mutational events in human skin cancers, both in specific genes and in large-scale genomic sequencing studies analyzing thousands of different genes simultaneously.
In addition to developing mutations in structural genes for drug targets, bacteria can become resistant after mutational events in motifs for gene expression, such as promoters (13 ), in regulatory modules, such as 2-component regulatory systems (14 ), or positioning upstream from a gene of a mobile (15, 16 ) or stable (17 ) promoter.
