I though I'd write a quick guide to Co-Dom genetics to help some people along.

Refence:
Allele - A gene or trait
Locus- A slot or place containing the Alleles for a trait

Fist is to understand that Co-Dom genes themselves can be Co-Dom or recessive to other genes in their locus. With BP we to this point have only dealt with Co-dom/co-dom genes.

Example

Pastel is Co-Dom to normal

When both genes are expressed in this locus we giving us a Pastel when two pastel genes are present in the locus there is no interfering coloration from the normal gene so the effect is a Super Pastel.


Now for a more advanced example I turn to corn snakes yet again.

Here we deal with three alleles (genes) that can share the same locus.

Montly is recessive to Normal
Stripe is recessive to Normal
Montly is Dom to Stripe

The montly or striped genes alone are recessive and act as such alone.
But they share the same locus and thus are co-Dom.
a snake caring one Montly and one stripe gene will show as monthly because no normal gene is present and monthly is Dom to stripe.