This little essay describs the Neutral Theory of Genetic Evolution in which the majority of evolutionary
mutations are considered selectively neutral.
The theory was originally developed by Motoo Kimura in the 1960s. One of its characteristics is the reliance on Genetic Drift to fix
an alele in a population. This is possible without traditional/Darwinian Natural Selection.
This is not
a nut-bar theory. It's simply describing a possible alternative mechanism for evolution. I've heard of a case involving
the shapes of sea-shells in intertidal zones where all
possible configurations, as defined by the physical/chemical constraints, were found in nature.
Basically the state-space of possibilities was simply 'filled out'.
Download the pdf here: Genetic Variation PDF