Germline mutations are affected by transcription.

<p><i>Panel A</i>, HGMD dataset; <i>y-axis</i>, as in <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003816#pgen-1003816-g001" target="_blank">Figure 1C</a>; <i>x-axis</i>, ratio of mutated NGNN sequences in protein coding genes containing the P2-guanine base on the non-transcribed (<i>NT</i>) <i>vs</i>. transcribed (<i>T</i>) strand; <i>solid circles</i>, HGMD dataset (<i>r</i>² 0.32, P(α)_0.05 0.991, P<0.001); <i>open circles</i>, 1000 Genomes Project dataset. <i>Panel B</i>, inherited splicing mutations dataset; <i>top</i>, cartoon of exon-intron boundaries showing the conserved GT and AG bases at the donor (<i>ds</i>) and acceptor (<i>as</i>) splice sites; <i>bottom</i>, graph of splicing mutations; <i>y-axis</i>, number of SBSs; <i>x-axis</i>, position of SBSs relative to +/−20 nt of splice junctions; <i>Panel C</i>, model for sequence-dependent SBSs in cancer and human inherited disease. In the first step, an electron is lost from within a tetranucleotide sequence, leaving a hole. In the second step, the hole migrates to and from various competing sites, including nearby bases and chromatin-associated amino acids (not shown), eventually being trapped by a guanine base. The resulting guanine radical cation either causes DNA-protein crosslinking or undergoes subsequent chemical modifications. If the modified base is not corrected by DNA repair, it may give rise to a mutation (X-Y base-pair) as a result of error-prone DNA polymerase synthesis during DNA replication (dashed arrow).