Well, not quite, what I was really pointing out is that the hypo gene in Hondos DOESN'T have anything to do with the typical amel gene.
The T-plus gene only seems to be allelic (co-dominant?) sharing the same allele with amelanism in Shannon's line of European nelsoni. But alot more has to be learned about that gene too like so many others in this hobby. It seems to be inherited like the PB/jelly traits in floridana, and the ultramel gene in the corn/grey rat hybrids.
Those are the only genes like this in colubrids that I am aware of. The actual term t-plus(tyrosinaise positive) has too many unknown factors to it to be honest. It can actually work all sorts of different ways, and with many variables, it can "seem" to be a form of hypo, or amel, or neither one at all and be totally independent of either one, and it actually IS most all the time with very few exceptions.
After learning more about it over the years, I actually now know LESS about it to be honest, if that makes any sense...LOL!. It is one complicated nut to crack Jimmy. That is why all the different so-called types of t-plus(lavender) animals out there have all these different looks. Because many different things can be going on in the pigment cells to cause them to look that way. It is similar to a ink drum leaking into a big swimming pool. The "ink" being the purplish colored tyrosinase, and the water in the pool is the melanin being produced in the pigment cell. All these different types of lavender, or t-plus looks can be caused by all sorts of different dynamics within the melanocyte that causes them to leak out no tyrosinaise enzyme, or any variable amount, and the genes responsible for the coding of these cells can reside at totally different places on the chromosome helix. So in essence, many of these looks might "seem" similar to something else in the hobby, but can be TOTALLY different genes altogether.
A true "T-plus" animal has tyrosinaise within the pigment cell just as ALL normally dark pigmented animals do, but it is kept from being mixed into melanin for unknown reasons and codes from the cells. The pigment cell retains tyrosinaise, and is stored there, but theoretically synthesizes NO dark melanin at all(which gives them the lavender/purple look we associate with t-plus, or lavender animals, or the cell synthesize just a tad bit into melanin, or even a more substantial amount of it can mix to produce yet more melanin within the cell, and of course would cause them all to look totally different and would be daker looking the more that is allowed to mix into actual melanin. But usually these mutant genes aren't allelic with the typical hypo or amel genes in the hobby, except for those other's I mentioned earlier. It usually is an entity all it's own, and is incompatible with other types(non-allelic).
This is why unless any of these different types of so-called t-plus, or hypo, or amel reside on the very same locus on the chromosome helix, it won't be passed on because it takes two(one copy from each parent) to make a visual homozygote of any of them.
I know the way I tried to explain some of it was probably very confusing, and it was pretty tough to even attempt to explain just a small fraction of it to be honest, but this is an area of genetics that is EXTREMELY complex to understand even the basics of, let alone throw all the terms around like most do when they can be as different as night and day.
Ohhh!, typing that even made MY head hurt man!..LMAO!!! 
~Doug
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"a snake in the grass is a GOOD thing" 
my website -Serpentine Specialties
Photo courtesy of Shannon Brown
