>In disputing whether,or not any of the boas which appear to be expressing tyrosinase positive albinism,have been clinicly,or chemicaly tested for tyrosinase activity...what I am saying is that visual criteria can be established to ascertain,or at the very least presume in the absence of microbiochemical testing,that an animal is expressing some sort of tyrosinase deficiency to the degree that constitutes a form of albinism.

I have no problem with stipulating that "tyrosinase positive" albinos have functional tyrosinase. I have no idea what the actual biochemical cause of their less than normal black pigment might be. But because of the presence of black pigment, though less than normal, I believe that they have functional tyrosinase.

I am not aware of any visual criteria on which to base more than the most tentative suggestion of tyrosinase impairment. On the other hand, lack of allelism with a tyrosinase negative albino mutant produces a high probability that the mutant does not impair the tyrosinase enzyme.

I did not make it properly clear that the boas that need testing are the Kahl and Sharp strains of albino. It is probable, in my opinion, that only one of them is tyrosinase negative albino. And the other has functional tyrosinase but is albino because some other enzyme is nonfunctional. That is the case in black rat snakes and gopher snakes. I just do not know whether to put my money on the Kahl or the Sharp strain. It is even possible that both have functional tyrosinase and that both are albinos for some other biochemical reason.

Paul Hollander

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