Toady DJ was taking class... she mentioned about Siamese Cat and related stuffs, the pigmentation pattern. One thing I found quite strange. She said, if we take a Siamese Cat to polar regions, it will turn into black completely! The logic was, since the temperature sensitive melanin producing enzyme (tyrosinase) will be functioning. I thought this was a rubbish idea.
Say we took a Siamese Cat to polar region (or incubated it in low temperature). If the mutant melanin producing enzyme had to function, the temperature of individual cells or tissues has to drop and more importantly the drop in temperature should sustain for a reasonable time (since melanin itself isn't mutant, rather one of melanin producing enzymes are mutant. You need time to synthesize melanin and make it express). This is quite unrealistic. In the extremities (or peripheral regions), the temperature is low. The reason being there is relatively low blood supply to exposed surface area ratio. High surface area is responsible for high heat loss rate, low blood supply amplifies the situation (Because blood is directly involved in temperature homeostasis). Theoretically in polar region, we may expect a Siamese Cat turn into completely black, but practically rapid temperature loss will lead to coma and eventually death long before you can see this bizarre hypothetical phenomenon.
Arguing with DJ has no point, those who know her personally will surely agree with me ;) .
