leucistity...little help please

No, Mendelian genetics works perfectly to describe what is happening. The confusion lies not in the ability to describe the method of inheritance, but the in the inability to accurately determine the nature of what is being inherited.

At this point you don't know what the snake is, whether you are referring to the phenotype or the genotype. Test breedings will help determine that.
You can only apply Mendelian principles after you have determined what you are dealing with.

A phenotype is just a vague reference point in finding out the genotype. Crap!!

Unfortunatly this is essentially true, especially in reference to reptiles. The problem is with the complexity involved in each process.
Take each pigment and prefix it with an "a", with "hypo", or with "hyper", then realize that each of these conditions are controlled at multiple loci and involve the participation or inhibitance of several enzymes. Then throw into the mix such conditions as leucism, piebaldism, calico, etc, and you see the extreme complexity of the subject matter. There also exists many traits in snakes particularly that remain misunderstood.
Gene mapping would be most helpful in furthering our understanding of the processes, but the probability of that being pursued anytime in the forseeable future is unlikely.
Only test breedings can shed light on the underlying causes of what you are dealing with.

I think you've got me convinced on the single non-specific pigment related gene theory. And until someone has a better idea or my breeding outcomes imply differently, it's the theory I'm going to go by...I guess.

I tend to agree with this theory. I believe leucism is controlled by a genetic process with much wider governing ability that those which control single pigments. I also believe that the genetic process responsible for this is not as complex as the processes it controls involving individual colors and patterns. This assumption would be supported by the fewer instances of the trait being expressed.
However, if your breeding outcomes imply differently, it does not automatically mean that this theory of leucism is inaccurate. It may also mean that you are not dealing with true leucism at all.
Remember, just because a breeder labels an animal leucistic does not mean that is what it is, look at the original "leucistic" leopard geckos.

So far as I know, Mark Bell is who originally produced these out of a captive collection and coine the term "leucistic" for them. I have never heard of anyone agreeing ith this term but for some reason we keep using it. Unfortunately, Mark Bell is MIA. If anyone knows how to contact him, let me know.

Hi ppl... I have kept quite a few Pituophis and other colubrids and boids and I think there's "marketing" forces at work here when it comes to names given to a strain..which can be very misleading... for example I bought a pair of "snow" cal kings off BHB a few years back but before I did, I asked is this genuine snow? (i.e. amelanism combined with anerythrism) or is it just a case of taking the blackest like, baja capes or something and crossing it with amelanistic and therefore getting a very white snake (that otherwise would be solid black) and he condifed "yes" it was a melanistic that was amelanistic genetically..
well I just bought a pair of mark bell leucistic s. pines and I wonder where they stand in this sense...they certainly don't seem to have alot of pigment in their eyes (not bluish like the texasrats) is it true leucism or just a albino patternless?
if the latter then i would be very disappointed..because leucistic to me means leucistic.. in the texas ratsnake sense..not some marketing term to butter ppl up with...(not that this has happened, I just want to know what they carry genetically)

as well with the tyrosinase pos. blk ratsnakes ("red phase" as opposed to "white phase") some called them lavendar black rat, which is alot more innocent than calling a patternless albino a leucistic eh?

anyway I'd be interested in hearing of the provenance of the so-called leucistic pines (mark bell strain or otherwise) and whether there are true leucistics or not (and whether his are or aren't)

Originally Posted by Patrick Dring

I bought a pair of "snow" cal kings off BHB a few years back but before I did, I asked is this genuine snow? (i.e. amelanism combined with anerythrism) or is it just a case of taking the blackest like, baja capes or something and crossing it with amelanistic and therefore getting a very white snake (that otherwise would be solid black) and he condifed "yes" it was a melanistic that was amelanistic genetically..

He said melanistic and not anery right? That would actually make them blizzards. There is no genuine snow cal king, how would you know if you had an anery? They are black and white already. Ive seen snow advertised which are just high white, very high white, so it could also be an amelanistic high white, but I dont think there is any anery traits in that snake.