Reptile & Amphibian Forums

Excuse my ignorance, could someone please explain T , or VPI T to me. Sounds like a variation of albino, but I'm not getting a clear explanation. Thank you soooooo much.

Sorry, I'm sure you knew what I meant. T-POS

The "T" stands for Tyrosinase. Tyrosinase is a copper-protein enzyme.
First of all this is all related to pigment in the Dermal and epidermal or layers of skin .Melanaphores are responsible for pigment changes through the synthesis of black and brown pigments known as melanin.This chemical process is melanosynthesis.Which is the conversion of the Amino Acid tyrosine into melanin.Tyrosine converts to dihydroxyphenylalanine (dopa), then converts to dopaquinone,but only when a catalyst is present.That catalyst is o-Diphenol oxidase (tyrosinase). Both the synthesis of melanin and tyrosinase occur in the melanosome.At this point Dopaquinone is modified into melanin is transferred onto dendrites and deposited in the appropriate melanophores.
So this is where the terms "Tyrosinase-positive (T+)" and "Tyrosinase negative (T-)" albinos originates.
In the T negative animal the catalyst Tyrosinase is not present in the melanaphore. There fore no malanin pigment is created ,this results in a animal possessing no black or brown pigment at all.
In the T Positive form the tyrosinase is produced but doesn't gain proper access to the melanaphore.Although there can be some form of leakage or minor transfer maybe by osmosis not certain resulting in slightly lighter melanin pigments yet darker then the T-Neg version.

. . . Lar M

-----
Boas By Klevitz
Boas By Klevitz

Thank you very much for your reply to my question. I guess I'm slightly confused. And again, please forgive my stupidity, but I'm working the "only stupid question is one unasked theory". I'm guessing a regular albino is T-, so what is the visual diff. in a T ? Slightly darker in what respect? I understand your explanation, I'm just having a hard time with it visually. T albino sitting next to a T-?? or am I missing a key ingredient?

Thanks again,
Chance

p.s. I'm looking for"Idiot's guide to T " !!

A T minus for instance original Kahl strain has no dark pigments at all
The VPI Caramel does have some variations of dark pigment but no black pigment.
Any place on a VPI T Pos Alb that's usually black on another Boa has an almost purple hue to it.
The rest of the darker color is a caramel color.
There are a few other versions of these probable T Pos Boas now a days.
Paradigms
Boa Woman Caramel
Podigy
Russian T Pos line
A Few lines are unproven as genetic still
Strawberry T Pos Line
Gerry's T Pos '06 fem

Plus the sharp Strain Albino is probably a very clean version
(Phenotype) of T Pos Albino at this point.
So in this case there is no real Phenotypical difference from
T Pos to T Neg .

. . . . Lar M

-----
Boas By Klevitz
Boas By Klevitz

Here are a couiple examples of VPI Caramel Albino Boas

. . . . Lar M
-----
Boas By Klevitz
Boas By Klevitz

Now I've got it, thanks for taking the time to help out the slow guy. I assure you it is MUCH appreciated.

Chance