EYE COLOR IN DANES: The Genes and What They Mean to Phenotype

By JP YOUSHA (August 2000)

Iris color, that is the color of the eye, is inherited independently of coat color. Which is not to say that coat color cannot influence eye color. Below is a chart I've put togther that shows the range of eye color, coat effects on it's basic "genetic" color, plus offers breeders an idea of how to relate phenotype to genotype (so we can work back from what we see to how we got it). Dilution genes (such as the Dane blue) affect skin and eye color as well as haircoat, so this chart reflects that potential variation from the actual GENETIC color of the eyes. Blue (Maltese) dilution the the Great Dane is a standard, accepted coat color. Red or brown dilution in the Great Dane is called "chocolate" and does occur in the breed. The "double dilution" (<bbdd>), sometimes referred to as lilac or lavender, is traditionally named Drapp in the Great Dane. In Danes spotting genes can result in "genetic" blue eyes and varigated irises as well (heterochromia iridis) as the merle gene can change the color drastically. For more on these other dilutions and coat color phenomenon in general, see the CHROMA-LINX index for specific articles on various effects.

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K9 EYE COLOR (Non/semi-technical explanation)
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Three alleles for eye pigment: Ir, ir^m & ir^y.
Six possible combinations:
Ir/Ir=BK(black-brown or black-velvet eye)
Ir/ir^m=Dk(dark-brown eye)
Ir/ir^y=M1(medium-brown eye-heterozygous)
ir^m/ir^m=M2(medium-brown eye-homozygous)
ir^m/ir^y=ML(medium-light eye)
ir^y/ir^y=L(light eye)

NOTE: Some would argue that this medium brown
eye of the heterozygote would be less stable a
color and some claim it's lighter than the true
breeding M2. And the below color descriptions are
not exact. Intended only as a guide of comparision.
And note below--the outcome when bred is different.

True blue eyes are a seperate phenomenon. Smokey
blue eyes are typical of young puppies & the color "clears"
to the adult shade by around three months typically. True
blue eyes are obvious pale & clear blue from the moment
the puppy opens its eyes. This effect in dogs is associated
with white coats. What the colors might translate to in the
eyes (irises) of dilute (blue, red, etc.) dogs listed below the
21 mating combinations.

21 mating combinations:
Bk x Bk=all Bk
If you breed black-velvet eyes, you get nothing but black-brown eyes.
Bk x Dr=1Bk:1Dk
If you breed black-velvet to dark brown, get 1/2 each shade.
Bk x M1=1Bk:1M
Breed black to medium eyes of the hybrid form (carries
for yellow), you get 1/2 like the black & half like the medium.
Bk x M2=all Dk
Breed black to the medium eye that is prepotent, you get
all dark eyes--not as black as the black eyed parent, but
all darker than the dark-eyed parent.
Bk x ML=1Dk:1M
Breed black eyes to medium light & get ALL darker than
the medium-light-eyed dog. Some medium, some dark brown.
(But none black-velvet.)
Bk x L=all M
Breed the black eyed dog to a light eyed bitch & get all a warm
coffee (medium) eye.
Dk x Dk=all Dk
Breed that dark brown eye to the same; all dark brown
Dk x M1=1Bk:1Dk:1M:1ML
Breed dark brown to medium of hybrid type & get some
of everything--Black eyes, Dark eyes, Medium eyes & one
even lighter than medium.
Dk x M2=1Dk:1ML
Breed dark brown to the prepotent medium brown & half
the litter is darker than medium (but not really black).
Dk x ML=1Dk:2M:1ML
Breed dark brown to a medium-light eye & get one
actually dark for two medium-dark and one medium light
like the lighter eyed parent--3 of four are better therefore.
Dk x L=1M:1ML
Breed dark brown to light and half are medium brown,
half are medium-light--none are yellow, if none dark brown.
M1 x M1=1BK:2M:1L
Breed two hybrid medium browns & you get the weird split
again---I actually BLACK eyed, two medium-dark & one
bird of prey eye. (That's how you know it's a hybrid.)
M1 x M2=1Dk:1ML
Breed that hybrid brown to a true (prepotent) medium brown
& you get one dark for every medium eye. NO light yellow &
no black-brown. Compare this with the one directly above.
M1 x ML=1Dk:1M:1ML:1L
Breed this hybrid brown to med-light--agin the weird split.
You get one really dark eye for one really light eye & two in the
middle, a sort of medium brown.
M1 x L=1M:1L
Breed that hybrid medium brown to a light eye & you get
half medium & half light.
M2 x M2=all M
Breed two true medium brown eyes & all are the same.
M2 xML=1M:1ML
Breed that true (prepotent) medium brown to a ligher eye
& half the litter is ligher than the darker parent.
M2 x L=all ML
BReed that true medium brown to the light eye and ALL
are lighter than one parent but darker than the other.
ML x ML=1 M:2 ML:1 L
Breed two medium light eyes. Since they are hybrids, you
get the split--one with darker, one with lighter, for every
two like the parents.
ML x L= 1ML:1L
Breed medium light to yellow(light) & you get a 50/50 split.
L x L=all L
Light to light gives you all bird of prey (bright yellow) eyes.

Note 21 combos are possible here: so lots and lots of
variation expected! For example, look at all the matings
where dark-eyed dogs will produce lighter eyes, & where
you see dark eyes coming from lighter eyed parents.
The dilution shades (below) are the best I could come up with.
Additions, corrections and better suggestions sought!
Best in general to use reference shades for comparison
(i.e. dark, med. lite) if trying for control & trying to keep accurate
breeding records, rather than try to describe each shade?

IN DILUTE DOGS THESE COLORS WOULD BE
DESCRIBED SOMETHING LIKE:
(NOTE: All these color descriptions are inexact and are intended
mostly for comparison. What these colors might translate to
in the eyes of dilute (blue, red, etc.) dogs listed below.)

Ir/Ir=BK(black-brown or black-velvet eye)
becomes in a blue dilute dog a chocolate color.
becomes in a red dilute dog a dark cinnamon.
becomes in a double dilute a clear coffee.
Ir/ir^m=Dk(dark-brown eye)
becomes in a blue dilute dog a khaki-grey/brown color.
becomes in a red dilute dog a red cinnabar.
becomes in a double dilute a hazel.
Ir/ir^y=M1(medium-brown eye-heterozygous)
becomes in a blue dilute dog an amber eye.
becomes in a red dilute dog a hazel eye.
becomes in a double dilute a yellow eye.
ir^m/ir^m=M2(medium-brown eye-homozygous)
becomes in a blue dilute dog an amber eye.
becomes in a red dilute dog a hazel eye.
becomes in a double dilute a yellow eye.
ir^m/ir^y=ML(medium-light eye)
becomes in a blue dilute dog a yellow eye.
becomes in a red dilute dog a yellow eye.
becomes in a double dilute a "clear" (pale) eye.
ir^y/ir^y=L(light eye)
becomes in most all dilutes dog a "clear"-coke bottle
sort of light green (maybe even called blue?) eye, as
so little pigment is now left, the eye isn't even able to
appear yellow anymore. There is in fact a sort of
"multi" dilute cream dog (Dondo/Cornaz) who may
end up with blue eyes from this sort of effect.

For more information on color genes and coat color genetics, see the resources and references below.

REFERENCES:
" Ackan, A. and W. Wegner. 1983. Veranderungen an Sehbahn und Sehzentren beim Merle-Syndrom des Hundes. Zeitschrift Fur Veruchstierkunde. 25(2): 91-9.
" Ackerman, Lowell, DVM. 1996. Dr. Ackerman's Book of Great Danes. Neptune City, NJ: T.F.H. Publications, Inc.
" Burns, M. and Fraser, M.N. 1966. Genetics of the Dog: The basis of successful breeding. Edinburgh: Oliver & Boyd.
" Carroll-Draper, Nancy. 1981. The Great Dane: Dogdom's Apollo. New York: Howell Book House.
" Cattanach, B. (1999). The 'dalmatian dilemma': white coat colour and deafness. J. of Small Animal Practice 40: 193-+.
" Clark, Ross D., DVM, and Joan R. Stainer. 1994. Medical and Genetic Aspects of Purebred Dogs. St. Simon Island, GA: Forum Publishing.
" Chopson, J. 1992. Inheritance of Great Dane Coat Color. GDCA Color Committee.
" Daush, D., Wegner, W., Michaelis, M. and I. Reetz. 1977. Opthalmologische Befunde in einer Merlezucht. DTW (Deustche Teirarztliche Wochenschrift). 84(12):468-75.
" Daush, D., Wegner W., Michaelis, W. and I. Reetz. 1978. Augenveranderungen beim Merlesyndrom des Hundes. Albrecht v Graff Archiv fur Klin. u. Exp. Opthal. 206(2):135-50.
" Flach, M., Dausch, D., and W. Wegner. 1980. Floureszenzangiographie bei Teckeln. Weitere Befunde zum Merlesyndrom des Hundes. 8(3):375-83.
" Gelatt, K.N., Powell, N.G., and K. Huston. 1981. Inheritance of micropthalmia with colomboma in the Australian shepherd dog. Am. J. Vet. Res. 42(10): 1686-90.
" Greibrokk, T. 1994. Hereditary Deafness in the Dalmatian-Relationship to Eye and Coat Color. JAAHA 30: 170-176. Hoskins, J.D. 1990. Veterinary Pediatrics: Dogs and Cats from Birth to Six Months. Philadelphia, PA: W. B. Saunders Company.
" Johnson, Di. 1994. Great Danes Today. New York: McMillian.
" Klinckmann, G., Koniszewski, G. and Wegner, W. 1986. Light-microscope investigations on the retinae of dogs carrying the Merle factor. J. Vet. Med. A. 33:674-88.
" Klinckmann G., Koniszewski, G., and W. Wegner. 1987. Lichtmikroskopische Untersuchungen an den Corneae von Merle-Dachshunden. DTW (Deutsche Tierarztliche Wochenschrifte). 94(6): 338-41.
" Klinckmann G., and W. Wegner. 1987. Tonometrien bei Merlehunden. DTW (Deutsche Tierarztliche Wochenschrifte). 94(6): 337-8.
1935. Dominant dilution and other color factors in Collie dogs. J. Hered. 26: 424-30.
" Little, Clarence C. 1957. The Inheritane of Coat Color in Dogs. New York: Howell Publishing.
" O'Sullivan, Neil. (1988-89) "Harlequin colour in the Great Dane dog." Genetica. 78(3):215-8.
" Padgett, George A., DVM. (1998) "Control of Canine Genetic Diseases." New York: Howell Publishing.
" Reetz, I., Stecker M., and W. Wegner. 1977. Audiometrische befunde in einer Merlezucht. DTW (Deustche Teirarztliche Wochenschrift). 84(7):273-7.
" Robinson, R. 1982. Genetics for dog breeders. Oxford: Pergamon Press.
" Schaible, R.H. and Brumbaugh, J.A. 1976. Electron microscopy of pigment cells in variegated and nonvariegated piebald spotted dogs. Pigment Cell. 3: 191-220.
"Sorsby, A. 1970. Ophthalmic Genetics. London: Butterworths.
Sorsby, A. and Davey, J.B. 1954. Ocular associations of dappling (or merling) in the coat color of dogs. 1. Clinical and genetical data. J. Gene. 52: 425-40.
"Sponenberg, D.P. 1984. Germinal reversion of the merle allele in Australian shepherd dogs. J. Hered. 75:78.
"Sponenberg, D.P. 1985. Inheritance of the harlequin color in Great Dane dogs. J. Hered. 76:224-5.
"Sponenberg, D.P. and Lamoreux, M.L. 1985. Inheritance of tweed, a modification of merle, in Australian shepherd dogs. J. Hered. 76(4):303-4.
"Steel, K.P., and C. Barkway.1989. Another role for melanocytes: their importance for normal stria vascularis development in the inner ear. Development 107: 453-463.
"Wegner, W., and A. Akcan. 1980. Auswirkungen der Merlefactors auf die Area optica beim Hund. DTW (Deutsche Teirarztliche Wochenschrift). 87(9):342.
"Willis, Malcolm B. 1989. Genetics of the Dog. New York: Howell Publishing.
"Yousha, JP. 1996. A Summary of Theories Concerning the Harlequin Variant in the Great Dane. Great Dane Reporter: M/A.
Yousha, JP. 1997. MANTLEDANE GENETICS: How to get & keep Boston-patterned dogs. Great Dane Reporter: M/A.

This message written and prepared by JP Yousha for the purposes of education.
All copyrights © remain with the author. However the author is willing to allow reprints upon request for educational purposes.
CHROMADANE 2000