What's an 'allele'?
Bashically.... its a gene. Or a specific form of a gene. There's a gene for eye colour, and the form of that gene that gives you blue eyes is an allele.
That statement is either so deep it would take a lifetime to fully comprehend every particle of its meaning, or it is a load of absolute tosh. Which is it, I wonder?
Terry Pratchett, Hogfather