Allelic variation. In sexually reproducing organisms, a gene
locus can be occupied any one of a number of different alleles.
Possible example: eye colour in humans - generally one colour per
person but different people have different colours.
Limits of this example:
- I'm not sure if a singe gene locus for eye colour has
- I think I remember something about eye colour changing
- Left and right eyes are different colours in some
animals. (How common rare is this)