Let me start out by saying that this is just wild speculation. I'm just putting forth a hypothesis with very little facts. Hopefully someone out there has the facts to quickly support or refute it (probably refute) but I just came up with this idea and want to run it by the community.
I'm NOT trying to slam any breeders or any morphs. This is just genetic speculation, nothing more.
Ok, here is the THEORY:
What if, caramel (aka xanthic, or T positive albino) and albino (aka T- albino) are different morph alleles of the same gene?
We don't really have to know how this could be as we could probably never be sure anyway but just for the purpose of this speculation lets say that albino removes or completely disables a gene critical to producing melanin and caramel just partially disables the same gene such that it only produces a faint shadow of dark pigment.
If the two mutations are alleles of each other (different mutations of the same gene) then if you breed a caramel to an albino you will not get any normals. This is because neither parent has a normal copy of that gene to give the offspring.
What would the double het caramel and albino look like? It could look like either parent, part way in-between, or something new. However, if we go with the idea that albino might be completely removing or disabling the gene, and caramel might just partially disable it, you might expect the double het to look like a caramel. If it's albino gene is a lack of function, them perhaps it's one caramel gene will function enough to make it look caramel (maybe a particularly light one, maybe no different than any other caramel).
If it happens to work out that caramel and albino are alleles of each other, then it would be impossible for an animal to have more than two copies of the genes for both mutations and normal combined. You could not have a homozygous caramel that was also het for albino. Any imported animal suspected to be homozygous caramel and also heterozygous albino would have to be only het caramel and het albino. Although it would be perfectly natural to look at such an animal and assume it was homozygous caramel (if that is what it looked like) and it would even produce all caramels when breed to a homozygous caramel (if caramel is dominant over albino per this theory) so of course anyone would reasonably think it was homozygous caramel.
The catch would be further down the road, particularly when it was bred to normals to produce 100% het caramels. Since this theoretical import double het male only has one caramel allele and one albino allele of this single gene only half of it's offspring would be het caramel and the other half would be het albino.
So, the outcome IF this theory where acurate would be that:
While both caramel and albino are recessive to normal, caramel is dominant over albino.
Any albino could not even be het caramel.
Any caramel looking animal could turn out to be only het caramel and het albino. The test would be to breed it to an albino and see if it produces only a large number of caramels (indicating that it is homozygous caramel) or a mix of caramels and albinos (indicating that it is a double het).
So, does anyone have any breeding results to prove of disprove this theory? Anyone ever breed a caramel to an albino?