More info about genetic variation: http://kaos.erin.gov.au/life/general_info/op1.html

A text summary of the clickable map above, meant for web-crawlers and other automatic tools:
genetic variation acted on by natural selection
genetic variation has characteristic 2 individuals rarely identical
genetic variation has characteristic genetic
genetic variation has characteristic heritable
genetic variation includes more fit individuals
genetic variation includes less fit individuals
genetic variation produced by mutation
genetic variation produced by sexual reproduction
genetic variation produced by meiotic recombination
genetic variation produced by viral/other gene transfer
genetic variation characteristic of species
genetic variation characteristic of population
genetic variation characteristic of living thing