Pattern or color?

[DianaM]

I've heard some say that bicolor, blanket, and saddle are patterns and also others who say they are colors. It would seem to make sense that bicolor, blanket, and saddle are patterns since we see sable dogs that have a saddle pattern, sable dogs that have a bicolor pattern, sable dogs that have a blanket pattern, and of course black and tan and other colored dogs with the same. What are the current theories on both?

[Chris Wild]

Black/tan is a color, in the sense that it is determined at the agouti locus. What genes are located on that locus are what determine if a dog is sable, self colored (black), black/tan etc....

Amount of black pigment expressed is determined by genes on the extension locus. This is what determines if a dog is a "saddle" pattern or "blanket" pattern black/tan, how dark a sable is, etc... While a black has these genes too, since it is self colored we don't see what genes it carries for extension of melanin expression.

Bi-color is believed by some to be a true color, located on the agouti locus. By others it is believed to be a pattern, located on the extension locus that turns a black/tan into a bi-color.

I am in the camp that believes bi-color to be a color. Why? Because if it were truly a pattern of black/tan, bi-color bred to bi-color or bi-color bred to black should produce some black/tan pups. Yet it never does. It always produces only bis and blacks, which would indicate that the genes for black/tan are not available. If bi were merely a pattern of black/tan, they would be.

[Brightelf]

Curiouser.. and curiouser! Then there are sables who DO have the "eye goggles" and those who do not, but are also just as dark. And then the rare dogs with EVERYTHING going for them to be a bi-coloir, but NO toe stripes/tarheels, where nobody wants to say "melanistic black and tan"-- because the dog is just so .. well.. bi-color! And beautiful and mysterious blacks with "bleed through," such as sable markings coming through on the inner stifle and inside of forearm. WOW. I love the variety in colors and patterns, even if I dunno always what to call 'em.

[Ceph]

I've always considered everything affected by the Agouti Locus as a pattern, not a color.

To me colors are things like the color of the black hairs (black, liver, blue, white (at the Dilution, Black and Extension Loci)) and the color of the tan hairs (red, tan, white (at the Intensity Locus)).

Chris -- I believe the Extension Locus only controls the mask and the white coat -- not the saddle and the bi-color....unless there is something new that I havent heard about. I dont think it *could* control the saddle...especially considering there are dogs with saddles but no masks, dogs with masks but no saddles, and dogs with masks and saddles...these combinations suggest that there are multiple Loci controlling that...not simply Extension.

The Extension Locus controls the following alleles (at least postulized by Sheila Schmutz...who is doing the majority of the major mapping research right now) :

E (extension) = melanocortin receptor 1 (MC1R) Examples with photos
EM = melanistic mask Examples with photos
E = eumelanin or phaeomelanin can be produced in hair
e = only phaeomelanin produced in hair

http://homepage.usask.ca/~schmutz/alleles.html

~Cate

[Chris Wild]

Originally Posted By: CateI've always considered everything affected by the Agouti Locus as a pattern, not a color.

To me colors are things like the color of the black hairs (black, liver, blue, white (at the Dilution, Black and Extension Loci)) and the color of the tan hairs (red, tan, white (at the Intensity Locus)).

I'm not sure there is an official term, but in general discussion with breed folks, when talking about "color" people are referring to if it's a sable, a black, a B/T. "Pattern" only seems to enter the discussion in a more laymen's term sense, with people asking if their dog is "saddle pattern" or "blanket pattern" to describe the overall look of the dog. Whereas most serious enthusiasts will just say the dog is dark/light, or may use the term melanistic, but don't tend to refer to "patterns" per-se.

Things like red/tan/silver/cream as well as blue and liver are typically (and correctly by my understanding) referred to as pigment, not "color".

Originally Posted By: Cate
Chris -- I believe the Extension Locus only controls the mask and the white coat

I may have misnamed the locus. Been several years since I read Willis, but the point I was making that overall color (sable, B/T) and how melanistic the dog is are controlled by completely separate genes on different loci holds true. The agouti locus determines if a dog is a sable or a B/T, but does not determine the extension of black pigment in that dog. That is controlled elsewhere.

[Ceph]

lol, I think everyone has a different view of terms When I think of pigmentation I think of the skin or the leather, which is also affected at the Black and Dilution Loci.

Color to me is Phaeomelanin and Eumelanin. Eumelanin is the darker pigment...which is affected by the Black, Dilution and Extension Loci....and the phaeomelanin is the lighter pigmentation, which is likewise affected by the Extension Locus in addition to the Intensity Locus.

I think the thing with genetics is that it's sometimes hard to go with some of the older geneticists like little, whitney and willis...they set the basis down for study...but even genetic hypothesis as late as 2002 can frequently be incorrect (sponenburg for example was following Willis' theory of white being caused at the Albino Locus)....things can change so quickly because up until recently all genetics was was an educated guess. Now that we are able to actually map genes...well...we're able to do more than hypothesize.

~Cate

[Chris Wild]

That's true, in it's strictest definition pigment refers to leather. But most seem to also use it to refer to the depth and hue of color in the hair as well, saying reds have good pigment, silvers have poor pigment, calling faded saddles to be poor pigment, etc...

[Ceph]

Yeah -- I've heard it refered both ways as well...I guess because in the White world we dont have poor coat pigmentation (or, in another persons view we might have 100% poor coat pigmentation ), pigmentation only refers to the leather.

The most basic way I think of it is that anything that dictates the way the phaeomelanin and eumelanin falls is more of a pattern....anything that changes the expression of those is more of a color. That's about the best way I can explain my way of thinking O.o

~Cate

[umzilla]

I bred my Fritz



to my Emi (sable with tarheels and pencil on toes)



Fritz has only been bred to saddles up until now, and all pups have been saddles.

Emi carries recessive black, as she has thrown black pups in the past.

We have 8 pups, 4 weeks old. Granted, they are very young and colors are developing.

2 sables. The girl sable is quite a bit darker than the boy, but shows more of a pattern.

The other 6 are B/Ts, but what a difference in the patterns and coloring they show thus far. Several seem headed to a blanket type, and others look like saddles in the making. I'll try to upload some pix this weekend to illustrate.

Christine

[lhczth]

All of the b/t puppies, though, will carry black (b/t from dad, black from mom) and the sables will carry b/t (sable from mom, b/t from dad).