Biased mutation spectra can change to help organisms find beneficial mutations more easily. By altering the types of mutations that happen, populations can discover new beneficial traits and reduce harmful ones. This shift in mutation patterns is good for evolution because it increases the supply of helpful mutations and decreases the burden of harmful ones. The direction of mutation bias can be reversed, which is always a good thing for survival. This change can happen through changes in DNA repair genes, which can be gained or lost over time in bacterial lineages. Overall, shifts in mutation patterns can be driven by natural selection and can make it easier for organisms to adapt and evolve.