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by wanderer on 19 January 2008 - 22:01
Here is a very interesting article on genetics relative to the Belyaev experiments in the USSR on the selection of silver foxes for tameness over generations.
Over the course of the experiment, spanning more than 40 years, they discovered that after many generations of selecting for only the quality of "tameness" other characteristics began to be established in the new strain, one of those being altered coat colour. This is a link to the entire article the whole of which is very fascinating:
http://www.floridalupine.org/publications/PDF/trut-fox-study.pdf
"Selection and Development" from the article by Lyudmila N. Trut in the American Scientist, Volume 87 1999
"Even novel coat colors may be attributable to changes in the timing of embryonic development. One of the earliest novel traits we observed in our domesticated foxes was a loss of pigment in parts of the head and body. Belyaev determined that this piebald pattern is governed by a gene that he named Star. Later my colleague Lyudmila Prasolova and I discovered that the Star gene affects the migration rate of, the embryonic precursors of the pigment cells (melanocytes) that give color to an animal’s fur. Melanocytes form in the embryonic fox’s neural crest and later move to various parts of the embryo’s epidermis. Normally this migration starts around days 28 to 31 of the embryo’s development. In foxes that carry even a single copy of the gene, however, melanoblasts pass into the potentially depigmented areas of the epidermis two days later, on average. That delay may lead to the death of the tardy melanoblasts, thus altering the pigmentation in ways that give rise to the distinctive Star pattern."
by FerrumGSDs on 19 January 2008 - 23:01
Great Article! Thanks for Posting. I do hope the Domesticated population survives also. :-)
by jc.carroll on 23 January 2008 - 16:01
Wow, Thanks for the article!
It's perhaps interesting to note that in fox farms there are incidents of the same traits as in the article occuring without deliberate intent as the farmers wind up selecting less aggressive foxes for their breeding programs. But the spotted pattern drastically reduces the fox-pelt's market value, and has been the bane of several farming opperations.
I used to hunt, and it was not uncommon to find a black bear with a white-patch on it's chest. Sometimes this fades as the bear matures, other times it does not. Black bears can and do come in a variety of colors, with Black (obviously) being the most common, but also brown, cinnamon, blond, blue ("glacier") and the rarest: white ("Kermode"). These alternate colors generally occure in isolated areas. Occasionally brown or cinnamon bears darken to black as they age.
I have not seen personally seen alternate colors of black bears, but I have a black White-Tail Deer once, and the occasional white-spotted one. I have never seen an all-white deer, though other people claim they have. This may be a bit off topic, but I figured I'd sharea photo. No, it's not mine. I found it online. The deer on the left is a normal-colored White-Tail.
Going back to the foxes, I found it remarkable how much the patterns looked like those on the herding breeds. But that's not a coat pattern I see often in other animal species, or even other dog breed groups. I'd expect to see it in other "primative" breeds like some of the spitz/northern-type dogs. I wonder if a lot of how the white is distributed depends on the dog's evolutionary ancestry. Though I've never seen a collie with a curled tail...
random a piebald White-Tail Deer; wild specimen.
by CrashKerry on 23 January 2008 - 17:01
There's a whole herd of white deer in upstate NY. The herd was trapped on a military depot when it was fenced in. Now that it's closed there's a movement to conserve the herd.
by jc.carroll on 16 March 2009 - 19:03
by katjo74 on 17 March 2009 - 04:03
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