There is a generic pattern for substitution mutations where some mutations are more common than others. In general, transitions are more common than transversions and CpG mutations occur at the highest rate. You can read more here:
In a previous thread I discussed what science meant by random mutations and how this term is defined by experimental results and statistics. A lot of this work was done in the 1940’s and 50’s, and since then many new facts have been discovered in the field of genetics, such as the discovery of DNA. This gave rise to the field of molecular biology and allowed us to understand biology at the molecular scale.
So what exactly causes mutations? We once again have to reiterate the the limited scope of science. What science can do is put forward hypotheses and see if the evidence is consistent with that hypothesis. What science can not do is make ontological statements about absolute truth. With that in mind, the next few posts will discuss the evidence that links mutagenesis (the production of mutations) with the biochemistry of the cell and why scientists aren’t simply assuming that mutations are caused by biochemistry.