Mutation
Etymology
From Latin "mutare" (to change), via "mutatio" (a changing). The biological sense — a heritable change in genetic material — was fixed by Hugo de Vries around 1900.
noun · /myoo-TAY-shun/
A change in an organism’s DNA, which may be harmful, harmless, or occasionally beneficial.
What it names
The raw source of biological novelty — the random typos in the genetic text that natural selection then edits, and the origin of everything from cancer to new species.
Example
A single mutation in one gene lets some adults digest milk into old age, a trait that spread wherever people kept dairy herds.
Related idea
Mutation supplies the variation; natural selection decides which variants persist. Mutation is blind and random, while selection is the non-random filter that acts on what mutation offers.