>>518993748
Mutation is not the primary driver of biological evolution. Natural, sexual and/or kin selection is, resulting in genetic drift.
Natural selection refers to whether a given life-form dies before passing on its genes or not. By definition, natural selection weeds out most detrimental mutations from a given population. Natural selection and inherent modification affect the frequency of alleles in a given population to either increase or decrease a trait's observable presence.
The epigenetic landscape plays a fundamental role in most biological processes that involve the manipulation and expression of DNA. The molecular mechanism of gene regulation is understood, but the hierarchical order of events and dependencies that lead to protection against infection remain largely unknown.
Random mutations do occur, but what drives evolution is selective and environmental pressures, adaptation in the form of mutations can occur very quickly depending on the species.