Reptile & Amphibian Forums

For several years I have seen several breeders, hobbyists, and enthusiasts use the terms tyrosinase-positive & tyrosinase-negative to describe the albino strains present in leopard geckos. My question is, what do you have to back up your claim? I am looking for scientific evidence showing that they either did or did not find tyrosinase being produced in the albino strain in question. I believe in leopard geckos this may be trickier then many people suspect. I for one do not think the terms T- or T+ can be applied at this time until further research has been conducted to prove the fact that they are in fact T- or T+. Some people say that the strains with the extreme red eyes are T-, but after researching this question repeatedly, I keep coming to the fact that T- eye coloration can range from grayish-blue to red, and the same for T+ albinos. All the information was gather via medical journals and related publications on the subject, not via an internet site. For months I have been searching for someone to test skin samples of the various albinos strains to find out for sure if they are either T- or T+, but no luck so far. Does anyone else know something I do not know and that is why I repeatedly see several of the albino strains (in leopard geckos) being referred to as T- and t+?
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Justyn Miller
Intense Herpetoculture

lab work has been done on these different strains, i feel their is more than ample proof that allot of what we are seeing are not true t- albinos, this is not directly related to leopard geckos but reptiles in general... i even think possibly some forms of hypomelanism maybe actually some sorta albino but in not sure

here are some things i looked up
i also downloades a pdf file i have yet to read but sounds interesting
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tyrosinase [?tair??si'neiz, ?tir??-]
noun an enzyme occurring in many organisms that is a catalyst in the conversion of tyrosine to the pigment melanin; inactivity of this enzyme results in albinism
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CARAMEL_ALBINO_BALL_PYTHON
Scientific Name: Python regius

The Caramel Albinos "AKA" Xanthics "AKA" T-Positive Albinos are one of the most beautiful ball python mutations. They are albinos........they have red eyes....and lack dark pigments. But they are a different type of albino.......when we think of albino.......we think of yellow and white with pink eyes.

The Caramels are ( T positive )........and the regular yellow and white albinos are ( T-negative )........the "T" stands for "Tyrosinase"........Tyrosinase is the enzyme essential in synthesis of melanin ( darker pigments )..........so an Albino that is ( T-negative ) will only be yellow and white because it "lacks" tyrosinase.......and a Albino that is ( T-positive ) will still be albino.......but will have darker pigments because it's tyrosinase enzyme is functional.

Real simply put........a T-negative's enzyme is turned off...........and a T-positive's enzyme is turned on.........one can produce darker pigment.........and one can not...........so there you have it..........two different types of Albinos.

from: http://www.ralphdavisreptiles.com/collection/pythons/ball/caramel_albino_ball_python.asp

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Tyrosinase - the enzyme essential in synthesis of melanin.
Tyrosinase-negative Albinism - albinism due to absence of tyrosinase.
Tyrosinase-positive Albinism - albinism in animals capable of synthesizing tyrosinase, but unable to synthesize melanin.
Tyrosine - the amino acid precursor of melanin, thyroxine, and adrenalin.

from: http://www.pkreptiles.com/genetics/glossary.asp
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this next link can not be copied and pasted but it contains some wonderful information
http://www.vmsherp.com/LCChromatophores.htm
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-robin struck
Geckoheads And Geeks

Maybe Kelli has contact with him, or someone could search the archives. I thought he had posted that someone was testing some albinosto determine they were T or T-. Anyone else remember this besides me?
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Rob Jenkins
Have you seen the GeckoCam?
Buy Geckos Here
Email Me

let alone a post from a year ago LOL
i hope someone knows or can find the archived file
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-robin struck
Geckoheads And Geeks

I remember him mentioning it a few times, he says it's been proven they're T .

We need to get his backup data for this, or references, etc.

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Rob Jenkins
Have you seen the GeckoCam?
[bleep]
Email Me

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Edited on January 6, 2004 at 18:21:33 by phwyvern.

Hmm, that would be interesting. I'll start searching. I don't remember though.

>>Maybe Kelli has contact with him, or someone could search the archives. I thought he had posted that someone was testing some albinos to determine they were T or T-. Anyone else remember this besides me?
>>-----
>>Rob Jenkins
>>Have you seen the GeckoCam?
>>Buy Geckos Here
>>Email Me
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Justyn Miller
Intense Herpetoculture

Vms, kelli and some of you others that are up to fte or have opinions about it
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-robin struck
Geckoheads And Geeks

My geckos were used all 3 strains.We took the tips of there tails off and then we did a dopa test and all 3 strains showed T ,You can send me your mailling address (snail mail) and when i get copies i will mail them out.This test was done in late 2000 or 2001.
Jodi L Aherns
Ground Gecko Freak

Should say we did a dopa test and all 3 strains T positive.

There was an article written quite a few years ago theorizing how hypomelanism and amelanism were intertwined. I want to say it was roughly five or so years ago and in The Vivarium if I recall correctly (I've got way to much info as it pertains to color morphs and coloration in reptiles to remember for sure). The gist of it was (once agian if I remember correctly) that hypomelanism was directly related to amelanism. Thus the selective breeding of lighter hypomelanistic animals could lead to the eventual production of an amelanistic animal. I'll try and find the article in the next several days and fill in the details.

Ian