color genetics - Page 3

Look closer at this picture of Zidane

Indeed he does.  Faded out, but still there.  It is still my educated opinion that DISTINCT toemarks and tarheels - now with the addition DISTINCT  - indicate black or bicolor recessive in sables.

molly

You are always in such denial that you could ever be wrong, it's truly amazing.  Zidane's markings are far more distinct than my dog's are close up.

I'm not usually wrong, Daryl - and the amazing thing is - what I know is from EXPERIENCE - not from book-reading like you.  Spend some more years breeding, producing, training, and hands-on experience before believing everything you read.  Your dogs' pigment is faded in general, no wonder  his toe markings are also faded.  Has he been Koered?  Is there a KKl3?  - or maybe you should try to stack him a little different so he is not so difficult to look at...

molly

I only qoute documented facts that support my experience.  Your perception is just warped, in more ways I can count.  You also lack a thorough understanding of how pigmentation works as well, while claiming that no one else's experience here could matter but your own.
 
There's two types of pigment (melanin).
Eumelanin - dark brown and black pigment
Pheomelanin - red and yellow (blonde) pigment

Gain-of-function Agouti alleles and loss-of-function Mc1r alleles each cause a pheomelanic phenotype, loss-of-function Agouti alleles and gain-of-function Mc1r alleles each cause a eumelanic phenotype, and animals carrying combinations of Agouti and Mc1r alleles with potentially opposite effects exhibit a coat color
phenotype predicted by Mc1r rather than the Agouti genotype; in other words, Mc1r is epistatic to Agouti.

~Mammalian Genome, Volume 15, 798–808 (2004)

A LOF mutation of the original wild-type agouti allele (sable) results in what we know as "recessive black", which is common in the german shepherd breed.  But, aside from that basic pattern, there are lots of varying degrees between the melanistic black patterns (eumelanins) found in sable and black/tan coats.

If the agouti locus were the only factor in producing these markings, then there would be a possible chance for you to support your "opinion".  But, as it happens, these two genes (agouti & Mc1r) are at odds with each other, and explain very clearly how a sable dog with very distinct markings doesn't carry a black or bi recessive, while a sable dog with faded markings can in fact carry the black gene.

These two genes at least, have been specifically studied in the gsd, while there are at least four that are positively connected with the coat-darkening colors in mice: the Agouti signaling protein (Agouti), attractin (Atrn), melanocortin-1 receptor (Mc1r), and mahogunin (Mgrn)

Well I have to agree with daryl on this occasion.  Though there is no doubt that the presence of the recessive black has an infuence of eumelanin distribution in wolf sables, it does not however seem to affect tanpoints (saddles, bicolours - same agouti allele). 

But to agree with Daryl's point, there are undoubtedly other genes at work in pigment distribution, and in the GSD, the extent of mask may be of influence but not MC1R.  GSDs do not have variation on the MC1R locus as they are exclusively (except for the possible presence of dominant black) k^y - yellow, that allows expression of the Agouti alleles.

Daryl - as usual - blah blah blah.  Why don't you agree that learning from experience, hands-on seeing for yourself is better than reading opinions?  Don't take my experienced opinion in favor of whatever book or internet drivel you are reading at the moment - time is better spent actually putting your hands on the dogs before opening mouth - I can't even read your messages - it is much simpler than that which you would learn if you actually bred dogs or trained successfully (which you  never have) - I'm sure you can do it - try harder!

molly

Baiting me with personal attacks doesn't make your experience any more valid, or my learning AND experience any less than it is.  I don't consider you a role model for success or proffesionalism by any measure.  I think you're just stubborn and "uppity" that you feel you're beyond reproach.  Frankly, I don't care if I breed survey my dogs, seeing little point in it for my purposes.  I've bred more than enough litters, and spend just as much time training as I do following academia.  Pick up a book and try shutting your mouth once in a while.

It would take titling your dogs before you can breed survey them.  I'm sure if you showed your dog in any venue, to any conformation judge they would tell you the faults and strengths of your dog.  Here's a  piece of advice - show off your breeding program by using the head shot on this dog - his head isn't too bad. 

It is very sad, that you used A) a dog with obvious pencil markings and tarheels, to demonstrate to me that I am wrong about all dogs carrying black or bi having these markings.  DUH.  and B) a black/tan dog to demonstrate that dogs without pencil markings/tarheels can still carry black recessive - anyone who knows anything about color genetics - book learned or not - knows that a black/tan dog with toe marks/tarheels is a BICOLOR.  And that not all bicolors carry black - and of course black/tans that are not bicolor can also carry black.  DUH.

If I'm wrong, then please show me a dog that is PROVEN AND KNOWN  to be dominant sable/sable - that has DISTINCT black toe marks/tarheels.  Or show me a sable dog that is KNOWN  to carry black or bicolor, that  has none. 

Here is the same female I showed before - the one who is a known sable/sable - she does have faded toemarks and tarheels, so yes I knew that too.  And I have seen Zidane several times in person, up close and personal.  His toe marks and tarheels are faded enough to not be noticeable. So no argument they are present, but still not convinced I am wrong about the color recessive being indicated by the presence or lack of these markings.