I'm not talking about Michael Jackson, I'm talking about Zoey. She is 25 months old, and her black nose has been changing to pink since Christmas. I think it is called a Dudley, but I was wondering why it is changing, and why now after two years?
Here's a picture, Merlot had to get in it too, his nose has always been pink
It's called snow nose and most yellows end up with it in their second winter. http://www.labbies.com/genetics2.htm#Nose
And what causes the noses of yellow Labs to fade during winter months?
The answers to both these questions can be found by examining the tyrosinase enzymes responsible for producing melanin from tyrosine. Some forms of these enzymes are temperature-unstable mutants that only produce melanins under ideal temperature conditions. Some tyrosinase enzymes work more efficiently in colder temperatures. Extremities, like the ears, are usually a cooler temperature than other parts of the body and as a result, the tyrosinase is able to produce more pigment in this region.
Conversely, the tyrosinase enzyme responsible for producing the dark nose pigment in yellows is unstable at low temperatures. Under conditions of low temperature, the tyrosinase enzyme stops driving the chemical reaction, and tyrosine conversion to eumelanin in the skin will occur at a much slower rate. As a result, pigment will fade.
Though certain drugs may also produce pigment fading, this latter cause for reduction in pigment occurs because these drugs will bind to dopa (an early precursor to melanin in the reaction from tyrosine to melanin) and inhibit the further chemical reactions that result in melanin. This condition will also cause fading of pigment in the Lab.
♣ Laura ♣
Thanks, Laura Very detailed answer!
Yup, what she said. Check out Frankie's bright pink shnoz in the pics I posted today in LC. It's jet black in the summer.
"Each is a creature of Earth and is entitled to reside on it with dignity"
Wow, I had NO idea that it could go back to black in the summer!! Frankie's black nose is so adorable!
They never go back to as dark as they were. They're darker but never as black again. Each winter they tend to lighten more until they're light all the time.
♣ Laura ♣
gosh I hope Rhumba's come back in some in the summer. Frankie's pic gives me hopeOriginally Posted by jzgrlduff
This is Bo's third official winter. The first one he was just 11 weeks old. The second he was just over a year, and now, he is 2 and his widdle nose is pinking. I was just so sad when I noticed it. But oh well, he is still my lover boy. :-*
Shane's nose has turned slightly pink too. It's black in the warmer weather.
Summerlin's Inspired by Armani CD (Shane)