Crash Course in Canine Coat Color Genetics
        (summary by Martine Huslig, MS, CGC--Certified Genetic Counselor)
The primary coat color genes that appear to be at work in the Briard are K, A, G, D and possibly C We would believe that Briards are "fixed" for the other genes and therefore we do not see those variations in colors regulated by those genes.

The interaction of two "types" of pigment (melanin) create canine coat color
        1)       Black/Brown (Eumelanin)
        2)       Yellow/Red (Phaeomelanin)
Genes
                A  -Agouti Locus
                        Ay-sable-aka clear tawny
                        aw-wolf color-gray/cream banded hairs
                        as-saddle and tan aka Charbonne?
                         at-black and tan
                         a recessive black

                K   -Dominant Black Locus (apparently a newcomer to traditional models of canine coat color genetics but apparently once compared to other mammals—A is the expression or lack of expression of Yellow red melanin and therefore dominant black is a separate allele--This is why black Briard bring their tawny colors with them to tawny breedings---otherwise they would have no affect on the tawny color of their tawny offspring or decedents but we know that they do.)
                        K-dominant black
                        kbr-brindle
                        k –“normal”  (augouti takes over)

                 E    -Extension Locus -Controls the expression of the Black/Brown pigment over the body) 
                        E-normal presentation of black over the body
                        e-a dog that is double ee will be entirely red/yellow based (Labrador Retrievers are all black per KK and E and B modify the "expression" of their black.)

                   B   -Chocolate Gene (lightens black/brown pigment only)
                        B-black pigment
                        b-black pigment lightened to brown

                    D   -Blue Dilution Gene affects both types of pigment but affects Yellow/Red pigment less dramatically
                        D- “normal” pigment
                        d – double dilutes black to blue
 http://skyway.usask.ca/~schmutz/dilutions.html- interesting explanations with picture illustrations

                    C   -Albino Gene (?Locus) (this series affects the intensity of the pigment production in the coat hairs---the mutant forms are TEMPERATURE sensitive –the higher the temperature the more effective they are at lightening the coat.  The reference says that most dogs are CC here but given the potential “changing color” in some tawny Briards it would seem that Briards do have the Chinchilla gene—yes?—(The exact order of lower alleles is apparently not certain but is suggested to be:)

                        C-full color
                        cch- chinchilla-lightens most or all of the yellow/red pigment with little to now affect on black.
                        ce- “extreme dilution”-causes tan to become almost white (possibly white lab) or perhaps West Highland White Terrier
                        cb- blue-eyed albino-white coat with residual pigment in eyes causing pale blue eyes
                        c- true pink –eyed albino—does not seem to occur in dogs

            G – Graying Gene
                        G –causes dog to gray with age
                        g  –no graying

            Se or Ma- Super-Extension or Mask Apparently previously thought to be part of E but now believed to be a separate locus
                        Se –mask present
                         se  -no mask

            S – White Spotting  (incompletely dominant making clarification more complicated and presentation is influenced by merle)
                        S Solid color
                        si “irish spotting”-white spotting on most parts of the coat but not across the back
                        sp more extensive than white spotting and often crosses the back
                        sw extreme white piebald- sw sw is almost entirely white

            T – Ticked—dominant mutation causing color in the areas affected by S (Dalmatian)
                        T – ticking
                        t- no ticking

            M – Merle partially dominant gene associated with ophthalmic and hearing problems-also a melanocyte specific protein necessary for the normal development of melanosomes
                        Mm – Merle pattern
                        mm – normal pigmentation

The information above can be outdated rapidly and canine coat color is an area of intense research interest.  We have found this site to be the most up-to-date on canine coat color research discoveries-http://homepage.usask.ca/~schmutz/dogcolors.html