Reptile & Amphibian Forums

I was wondering what the difference is between the two. and also what does the T stand for? thanks for any and all help
wayne

Amelanistic and albino are more or less synonymous terms meaning a lack of black/brown melanin pigment.

A T-negative albino is a snake that lacks melanin because it makes a nonfunctional version of an enzyme named tyrosinase. The T in T-negative and T-positive stands for tyrosinase. Tyrosinase catalyses the first two steps in the series of biochemical reactions that synthesizes melanin from the amino acid tyrosine.

The link below will tell you about the dopa test for tyrosinase activity. Possibly more than you want to know.

The T-positive (kingsnake.com will not display the plus character) albino lacks melanin for some reason other than a nonfunctional tyrosinase enzyme. Presumably, such snakes have a functional tyrosinase enzyme. Depending on who you talk to, T-positive albinos could look like T-negative albinos, or they could have some melanin, though less than the normal amount of melanin.

Boa constrictor fanciers are particularly screwed up over T-neg and T-pos albinos.

There are two mutants in boa constrictors that seem to act in different ways to prevent the formation of melanin. Both are often described as T-negative albinos. But as far as I know, no albino boa or python has been through the dopa test. Without that, there is no way to know whether an albino is T-negative or not. Odds are that only one boa constrictor albino is T-negative, but it is possible that neither is T-negative.

There are two independent mutants in boa constrictors that are described as T-positive albinos. Both have some melanin.

Hope this helps.

Paul Hollander
Two Types of albinos in San Diego gopher snakes