Hello Beverly,
Thursday, April 05, 2001, 5:46:25 PM, you wrote:
BE> If Tremper x Rainwater gives 100% normals, and the two types of albino
BE> assort independently, they *have* to be mutations of different genes,
BE> don't they?
No, they could also be different alleles of the same gene, the gene
for tyrosinase, in this case.
BE> It seems that the amount of brownish pigment expressed in a Tremper
BE> albino may depend on some environmental factor, possibly temperature or
BE> light exposure.
That's a great idea.
Another possibility, and I think this may be what is happening with the
Tremper mutation, is a 'leaky' mutation. A 'leaky' mutation, in
contrast to a 'null' mutation, which would cause no tyrosinase
activity, could still convert tyrosine to dopaquinone (the main job of
tyrosinase) but in a reduced capacity. OCA1B, a human form of t+
albinism, produces tyrosinase that produces dopaquinone (and therefore
melanin) at 1-10% the rate of 'normal' tyrosinase. This variability
(which differs in every individual) produces people with virtually no
melanin to folks that can get a light tan! It's a similar trait that,
I think, is responsible for 'hypo' cornsnakes. They can be almost
normal looking to almost amelanistic. The amount of melanin produced
varies from snake to snake. Sound like the Tremper albinos?
Imagine a mutation that, when the enzyme folds into it's tertiary
structure, it's a little different every time (Tremper). Compare this to an
mutated enzyme that folds the same way every time, but still operates
in an inhibited manner (Rainwater). You would have two different alleles, one that
produces a variable, leaky tyrosinase molecule and another
that produces a stable, leaky tyrosinase molecule.
I'll, hopefully have this worked out in the near future.
--
Best regards,
Tony mailto:[EMAIL PROTECTED]
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