discontinuous variation – characteristics in organisms which have limited (yes or no) variation

To remember the meaning of discontinuous variation, use the following mnemonic:

The path was discontinued so the fairy (discontinued variation) had to jump the gap to the next path with nothing between them. She would either make the jump (YES) or not make the jump (NO).

Discontinuous variation refers to characteristics that fall into distinct categories with no intermediate values between them, either yes it's got it or no it hasn't. These traits are controlled by a single gene or a small number of genes and show clear-cut differences rather than a range of possibilities.

Examples

Discontinuous variation examples include the following:

The ability to roll your tongue, or not;

Your blood group

and whether you have attached or free earlobes.

Unlike continuous variation where there's a spectrum of values (like height or weight), discontinuous variation produces separate groups that don't overlap together. Environmental factors typically have little to no effect on these characteristics since they're determined purely by genetics.