WHITES: IS IT WORTH THE RISKS?*
OWNING & BREEDING
A. OWNING: White Danes are dogs who
generally are "at least" deaf & may well suffer from a variety of
other congenital and inherited defects associated with lack of pigment, which
is not confined to the hair & skin in the white Dane, but can cause
multiple defects in various structures to include particularly the sensory
system which develops in close contact with the skin system in early embryo
stages. Below is given a list of defects specifically associated with the white
merle (MM= homozygous merle=double merle=dominant/defective white) Dane.
Piebald coloring with extensive pigment loss also
results in deafness quite commonly as it does the Dalmation,
and a series of articles is listed at this site that discuss the generally
unsuccessful attempts to raise and keep safely a deaf dog as a pet. (Danes can
carry both piebald white & merle white genes, so are at increased risk for
defects over most other "white" dogs, esp. deafness & sight
defects.) To see a typical white up close, click here. Dogs being sold as "merlikins"
"lightly marked harlequins" "white & blue," "white
with markings," "white with blue eyes," etc. are all at risk. A
gallery of dogs referred to as whites can be found here: note these dogs mostly all ended up in rescue & all
of them are said to be deaf-all. For more info on neural crest development see: http://www.teaching-biomed.man.ac.uk/student_projects/1999/moran/ or http://www.google.com/search?q=neural+crest+development&btnG=Google+Search).
The unemotional fact is
that rescue fills up with deaf Danes as most cannot be kept as pets. It is also
a GDCA Code of Ethics violation to knowingly sell a defective (unhealthy) pup
as a pet, and any harl breeder worthy of the name knows that white pups will
usually suffer from a variety of unpleasant problems which may well continue to
arise (and surprise) the owner thru the first year or longer. Many animal
welfare organizations endorse humane euthanasia for ALL (bilateral) deaf
puppies for the puppy's sake, and
most white Danes are not only deaf, but may have eye and skin problems as well.
Something to think about before condemning breeders who euthanize pups with sensory defects or applauding those who
do not. This is not, forgive the pun, a black and
white issue. See the list below for the defects associated with White (double
merle) Danes and note many of these are very serious problems, not all of which
are obvious to the casual observer at 2-3 months. Note also that apparently
about 50% of white merle dogs are so defective they do not survive to birth. So
the ones we see are the ones with "just minor" defects--minor enough
that is to have not ended in fetal death. But a gene
that kills 50% of those carrying it (in a double dose) cannot be dismissed or
ignored. Recall also that "just" deafness & "just" poor
sight are not so minor to a dog, and the lack of proper sensory equipment is
for them a hardship indeed. Such dogs not only normally need a
"helping" dog to get along day to day, the bite incidence and car
accident incidence in sensory-deprived dogs is *VERY* high--as high as 80% by
some studies. Certainly there are success cases in keeping an otherwise
"healthy" deaf dog, but these success cases are far outnumbered by
the failures. Not a nice life it would seem, is in
store for the average deaf and/or blind Dane. Hence the reason most responsible
breeders usually do NOT offer them up as pets but under very rare situations to
people, for example, they know well who live nearby, and when they do they give
them away--they do not sell them.
1.
Congenital CATARACTS associated with micropthalmia.
Blinding disorder.
2.
Persistent papillary membrane.
Can be blinding, is disfiguring eye defect.
3.
Tapetal hypoplasia. Lack of reflective lens. Can cause night blindness.
4.
Convergent strabismus.
Cross-eyed – affects vision.
5.
Enopthalmia – recessed eyes – can lead to chronic infection.
6.
Micropthalmia – tiny eyeballs – often lead to total blindness
and most have very poor sight from the start.
Often the eyeball must be removed.
7.
Medial canthal syndrome – when (commonly)
associated with 5 and/or 6 – leads to chronic infection and blindness.
8.
Heterochrommia iridis/hypochromia iridis – lack of iris pigment – causes blue eyes and is
associated with deafness and can be associated with other eye defects in
predominately white dogs.
9.
Colomboma(ta). “Notched” irises and other eye structures
which fail to develop properly and close on the suture lines due to the action of
the Merle gene. Leads to various defects
of vision and even collapse of the eye structure.
10.
Merle deafness – develops in the first month of life and is
permanent and often debilitating to proper social development of the dog. Usually bilateral; testable by no later than
6 weeks; associated often with other less apparent defects. Euthanasia is recommended.
11.
Piebald deafness – is present normally by 4-8 weeks and bilateral
deafness can only be objectively confirmed by a BAER test. When bilateral, euthanasia is recommended.
12.
Demodicosis.
Immune-mediated hair follicle mange.
Increased incidence is reported in harl Danes and especially white and
merle pups.
13.
Atopic dermatitis. Inherited
allergies. Increased incidence is
reported in harl Danes and especially white and merle pups.
14.
Skin cancer. Increased
incidence is reported in harl Danes and especially white and lightly marked
harl and merlikin pups due to lack of protecting
pigment (melanin) from UV (sunray) exposure.
Sunburn also occurs often in dogs lacking pigment and this can lead to tumors/cancer.
15.
Follicular dysplasia. A hair coat problem of broken and dull hairs
and “pimply” infection with a high incidence in white coated (and other dilute colored dogs).
16.
Photo-induced epilepsy. Seizure activity reported in white (double
merle) Danes thought to be associated with subtle eye structure defects.
17.
Sterility and reduced fertility.
Increased incidence reported in some mostly white pups.
18.
Multiple congenital defects.
White pups may have a variety of organ defects which arise only as they
grow and first may only be seen (if seen when young at all) as a (i.e., “runt”)
failure to thrive and keep up with the size, weight and activity level of the
other pups, but later results in multiple health problems for the dog. Bear in mind that about 50% of the MM=double
merle whites do not survive to birth.
19.
Social instability and inadequacy.
Dogs with sensory defects commonly are unable to interact with their own
species as well as with humans with full and satisfactory success. Such pups may well be identified, isolated
and treated as different right from the start by the dam and other
littermates. Many develop poorly, fail
to adapt and have multiple problems coping with normal daily activities; they
are often described as “shy” or “spooky” and the bite incidence for such
animals is high. Some are picked on,
most have trouble with normal events, especially those involving more than the
immediate family (the vet, boarding, etc.), while
others need another pet constantly with them to cope with the world at large
and suffer tremendously when this animal is not near them. Death by automobile is a common end for such
dogs, but most are simply given up to rescue when they become too huge a burden
for the family who bought them as a pup.
Many will never be placed due to their poor social skills. Of course there are success stories – but you
cannot plan on being one of them necessarily.
B. BREEDING: White Danes first and foremost
*ALL* have a DISQUALIFYING fault of color. Dogs with
disqualifying faults can be registered, but not ethically bred by many people's
standards. Some breed clubs and registries and even some countries control the
breeding of merle dogs just to avoid the production of these white merles.
White (merles) used in a harl breeding program, MM "double merle"
whites carrying the harl factor, are statistically less than 15% of dogs born
appearing as predominately white. These candidates for harl-production are
nearly always deaf & usually have eye defects, often so subtle they are
missed unless a CERF exam is done. Deaf stud dogs may be manageable by
experienced people, but bitches rarely are. Both may well try to escape to get
mated, and, a deaf dog, unsupervised in public is very likely to be hit by an
automobile and killed. A deaf dog is often more difficult to rear, so, as a
stud dog, he may be a challenge to collect and to breed. Some are sterile and
others are too behaviourally aberrant to breed properly. Health checks are more
complex with an obviously defective dog, and the better sort of bitch owner in
general doesn't choose a deaf white as the first choice for a good bitch, so
the quality of his offspring will likely be poor, as the bitches who frequent
him are likely to be of lesser quality than those going to a Champion/finishable Mantle or Harlequin. A deaf brood bitch cannot
often raise a litter successfully at all and she will, as a deaf bitch, need
help. She cannot hear her pups and deaf bitches will kill some of their pups by
crushing them and lose a few more by not knowing they are strayed too far, so
they die of cold. Many have NO maternal instincts and will not accept the pups
at all; some savage and kill them. You would have to be with them practically
24 hrs a day until they were old enough (2 months) to go, to be sure they even
survived and there is no guarantee she will even feed them. It is so hard to
even try this when you are an expert and anyway, pups raised this way
(essentially as orphans) may never be truly normal, even if they do make it.
Lots of things are said about whites to justify breeding them, but whites are a
gamble really and unnecessary to a Harlequin breeding program. It is true you
can breed the "right" sort of white to a "black or
There are at least
THREE obvious general genotypic classifications for the "white" Dane
are well documented (with likely subcategories).
1.
Dominant (double merle) white (MM).
(The “typical” deaf white with no head pigment, a spot somewhere on the
body.)
2.
Recessive (piebald) white (mm).
(The dog with a cap of black on its head, a big round/oval spot over the
ribs/tail root.)
3.
Hybrid white (Mm). (The “light
marked” harl, at least some of the time.)
Under the category of
Dominant white, two further genotypes (for the same phenotype) likely exist:
harl-factored (HhMM) and merle-only (hhMM). Only one of which is even potentially useful to a
harl breeding program (and that the one likeliest to be defective). A further
sub-category of three variants at the S locus may also exist in lines that
produce "white harls" & "merlikins" (HhMmss/hhMmtwtw)
and/or other piebald whites (mmss). [ss as shorthand for sp/sw]
Under the category of
Recessive (piebald=Boxer) white, three basic genotypes (for the same phenotype)
exist: sp/sp sp/sw & sw/sw.
None of these "double recessive whites" are of ANY use to any harl
breeding program--they are "affecteds" who
spread the genes for undermarked, white bodies dogs
(i.e. white-factored harls and mantles) which confuse
the issue in harlequin breedings while making all
their offspring carriers of mismarkings.
Under the category of
Hybrid white, you have dogs which carry all the problems of the above two
categories (being a hybrid of them both), so are potentially the most
confusing, and therefore damaging of all to the gene pool, as the most
difficult to identify and least predictable in their offspring. At least 50%
are obviously incapable of producing the harlequin variant, as they lack the
harl factoring at M (i.e. the "H" factor).
This gives 21 (TWENTY
ONE!) GENOTYPES for the "WHITE DANE" and of those 21, ONLY THREE (3)
are potentially useful to the harl gene pool, with only one of those three
being true breeding, (the other two being hybrid, thus adding to even MORE
mismarks) and that true breeding one almost always defective, difficult to rear
and care for, a disqualification under the standard, and with no guarantee of
quality offspring or even of being fertile. (Note: For simplicity's sake I have
avoided the extra complication of the
Just to look at all the
potential genotypes for the "WHITE" Dane that correspond to that
single phenotype (white) and you can understand why it generally makes no sense
to risk rearing and breeding these animals. (Add to that the difficulty,
especially with a deaf female, of successfully keeping her to breeding age,
then her breeding and rearing a healthy litter?) There are exceptions, but most
quality harlequin breeders rarely if ever use mismarks in their breeding
program. The odds of producing correctly marked animals is so poor (and this
world is already overflowing with mismarked dogs,
please), the "gamble" seems hardly worth it to the breed and the
general dog population, let alone the breeder at hand, and better choices,
really, must generally be available to the conscientious and knowledgeable
breeder.
AND THIS IS COURTESY
of Neil O'Sullivan, Ph.D. (who is listed in the references as an author on
harlequin color); geneticist, second generation
breeder of Danes & Chairman of the GDCA Color
Research Committee:
"I have had a number of emails this year asking about breeding
deafs. My advise<sic>
is always the same. Don't do it.While the placement
of pigment seems almost random on homozygous merles (Whites...most in fact have
some color), harlequins and merlequins,
it in fact is not totally random. You will note that the somatic mutations
which causes otherwise white areas to turn gray or
black occur more frequently on the head around the ears and eyes and over the
rump and the top of the tail. I speculate this has a selective advantage and so
nature has selected for genes which interact with the MM hh,
Mm Hh, and Mm twtw
genotypes to prefer pigment in these areas. Thus the MM is more likely to be Mm
or mm on the head (especially near the ears and eyes) while the rest of the
body is still MM (and therefore white)."
"You will note that the use of deaf
whites is highly correlated with more deaf whites in the progeny or grandprogeny. Also the use of deaf whites and deaf merlequins correlates with a higher incidence of deafness
and eye defects even in the harles. Also hearing
whites, merlequins and others have a higher frequency
of hearing in their progeny too. You will note of the White dogs I knew Laura
(BMW) to breed all could hear, Vanilla, Johnny and YamYam
for sure.
"I am assuming you know the basics of harlequin color genetics here. A harlequin is HhMm
in genotype with the gray of the merle genotype
converted to white by the Hh genotype. Thus the
Harlequin is predominantly a White dog with black torn patches, a merle is (hh Mm) a gray dog with black torn
patches and a merlequin is a modified merle ( hh Mm tw
tw). A harlequin with tw tw genotype is usually a "mixed" color with almost as much merle as black patches. Tw the non tweed allele is dominant. But I digress."
"In short...I think breeding from deaf dogs is not smart as it increases
the frequency of genes which do not encourage pigmentation of the head and thus
middle ear and retina and in so doing not only set us up for more deaf whites
but deaf merlequins and deaf harlequins too. Yes,
deaf harles, as you know from rescue are not as rare
as we breeders would like.
You may quote this if you feel it it helpful."
*WHITES* really should be limited to describing the genotype MM: a homozygous
"double-merle=white merle" dog, which is not always all white in
appearance. But, by phenotype (appearance), rather than genotype (genetic
identity), many dogs are called "White," so all potential iterations
of what could be a white-by-appearance/registry Dane are discussed.
"Whites" who are mm=piebald white should actually be registered as B&W
dogs and are a kind of mismarked Mantle;
"whites" who are Mm should be registered as mismarked
harls (HhMm) or maybe
merles (hhMm) (if you could sort them out from the
true whites, that is), so that MM whites can be properly identified. But this
logic is not currently applied, and dogs are simply identified by appearance and
registered at will, often without consideration to genotype. This makes reading
pedigrees difficult and it's hard to truly know the genetics of these white
parents often. Yet another strike against them for many
people who want to have properly marked pedigrees. For more information,
details of inheritance and further reading, see the
references listed below.
Harl=H is a dominant
factor postulated to "take the grey out of the merle" dog, thus producing
the Harlequin variant. Double dominant harls (HH) do
not exist, as, under this theory, the homozygous state is lethal to *all* the
embryos. All living harls are Hh
hybrids. They also are Mm merle hybrids. Merles lack the H=harlequin factor and
thus cannot contribute to the production of harls
(neither can merlikins, except to help produce
improperly marked "tweed" harls).
Blacks/Mantles from Harlequin breeding could, in theory, carry for the
Harlequin factor. Thus some (not all!) Mantles, for
example, can contribute to the production of harls
when bred.
Tweed=tw is a recessive factor postulated to give a mixed "swirly" look to the grey-to-black areas, with lots of
ticking/flecking in the merle patches, & a lack of distinct, crisp black
patches on the harl.
Another article on the White Dane
Dr. Strain's
article on deafness & its recognition
Dr. Cattanach's article on
deafness, white coat & blue eyes
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.
Burns, M. and Fraser, M.N. 1966. Genetics of the Dog: The basis of successful
breeding.
Carroll-Draper, Nancy. 1981. The Great Dane: Dogdom's
Apollo.
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.
Chopson, J. 1992. Inheritance of
Great Dane Coat Color. GDCA Color Committee.
Daush, D.,
Wegner, W., Michaelis, M. and
Daush, D.,
Wegner W., Michaelis, W. and
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.
Green, B.K. 1974. The Color of
Horses. Flagstaff, AZ: Northland Press.
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.
Klein, E., Steinberg, S.A., Weiss, S.R.B., Matthews, D.M.,
and T.W. Uhde. 1988. The relationship between
genetic deafness and fear- related behaviors in
nervous pointer dogs. Physiology and Behavior 43:
307-312.
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.
Krautwurst, Friedmar. 1997. Harlequin Breeding
Forbidden in
1991. Die Deutsche Dogge.
The MERCK Veterinary Manual, 6th Edition. (1986)
Nouc, Winfired. Deutche Dogge: Das Rasse-Portrait. 1990. Muerlenbach: Kynos Verlag. 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."
Reetz,
Robinson, R. 1982. Genetics for dog breeders.
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.
Siegal,
Mordecai, ed. (1995) UCDAVIS Book of Dogs.
Sorsby, A.
1970. Ophthalmic Genetics.
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 A. T. Bowling 1985. Heritable syndrome of skeletal defects in a family of Australian
shepherd dogs. J. Hered. 76(5): 393-4.
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.
Return
Home
Copyright
1999 (revised 2001) J P Yousha, CHROMADANE. All rights reserved. Our thanks to the willingness
to share this article for educational purposes.