Dog World news archive - February 2012

KC to cease registering Dachshunds from dapple parents

26 Nov 2009 08:02

This article has 17 Comment(s)

DACHSHUND puppies whose parents are dapple and have resulted from matings on or after January 1 will not be registered by the Kennel Club.
The KC has agreed the move after a request by the Dachshund breed council because the merle allele – one of a series of different forms of a gene – increases the risk of impaired sight and hearing.
Coat colour in the Dachshund varieties is complex because a range of colours is acceptable, the KC said this week. Dapple patterning, patches of lighter colour appearing in the coat, is the result of the M gene in the dog. There are two alleles of this gene: MM (merle) and M+ (non-merle), with merle (MM) being dominant to non-merle (M+). In some breeds, the effect of the merle allele (MM) is termed ‘dapple’.
“Unfortunately, the effects of the merle allele (MM) are not confined to coat patterning and we know that there can be an increased risk of impaired hearing and sight associated with it, particularly in dogs who are homozygous for MM (dogs who carry two copies of the MM allele),” a spokesman said.
“Many breeds are aware of, and for many years have dealt perfectly adequately with, avoiding the consequences of these health issues. However, at the request of the Dachshund Breed council the General Committee has agreed that with effect from January 1 the KC will not accept the registration of any Dachshund puppies from matings which take place on or after this date, where both parents are dapple.”
The KC said that at present there will be no changes in other breeds which have merles. “Any request from other breeds would be considered separately,” the spokesman said.
DOG WORLD breed note writer Jeff Horswell said he was delighted by the news that the KC had taken the step as requested by the breed council with the support of all breed clubs.
“This is very much a health issue,” he said. “Dapples must never be mated to dapples.
“Sadly, people do undertake this mating, either through ignorance or in an attempt to breed ever more exotic colours.”

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    1

    Given the double-merle risk, it would be good if this was now be implemented across the board - so Aussies, various collies, Old English Sheepdogs, Great Danes etc. And perhaps the KC could write to the relevant breed clubs suggesting it rather than wait for them to approach the KC? Jemima

    Posted at 08:53 on 26 Nov 2009 by
    jemimaharrison | Report as inappropriate

    2

    HERE HERE jemima, will the KC anounce on the front pages of DW that they have banned the dachshund breed council and breed clubs from weighing miniatures,

    Posted at 10:16 on 26 Nov 2009 by
    norm | Report as inappropriate

    3

    I think the kennel club would do better by registering all dogs of any colour and use the endorsment option on health grounds on undesirable colours in breeds with known problems instead of blanket bans of registering pups. After all surely its better to know to is producing them so hopfully they could prevent these type of problems occurring.

    Posted at 10:52 on 26 Nov 2009 by
    jos | Report as inappropriate

    4

    This is madness. Rather than breed heterozygous merles as any other sensible breed does the Dacshund breeders have bred 'double dapples' or dogs homozygous for the merle gene and they are surprised when deafness is a problem. Why condemn every other sensible breeder of merles by the banning of any merle breeding? I breed merle border collies and I always mate a merle to a solid. Simple! No problems!

    Posted at 11:30 on 26 Nov 2009 by
    Coires | Report as inappropriate

    5

    Coires. It would appear you have misread,. It is the mating of two Dapples, i.e. TWO merle parents that is being banned, which is exactly what Merle breeders with knowledge and integrity do. Sadly not all people who produce litters are knowledgesble or ethical. As I understand it this double dapple breeding is a fashion fad among puppy farmers in the US, and as with most things has migrated to this country, so the Dachs breeders have very sensibly asked for it to be banned within the KC arena,a nd it would make sense for other breeds to follow suit. This would be a very wise move as there are those who would have all Merle breeding banned, it was one of the points proposed in European Welfare legislation.

    Posted at 15:37 on 26 Nov 2009 by
    Brainless | Report as inappropriate

    6

    Brainless - My issue is with the comments made following an extremely poorly written article. Here is a direct quote from the article which is misleading "because the merle allele – one of a series of different forms of a gene – increases the risk of impaired sight and hearing". Now people who read this article who don't know very much about merles and their breeding might think that means all merles have an increased risk of impaired sight and hearing which is simply not true. Correctly bred merles (without the 'double merle risk') have no more risk of being blind or deaf than any other colour, hence they are not an 'undesirable colour'!

    Posted at 23:27 on 26 Nov 2009 by
    Coires | Report as inappropriate

    7

    Coires - The writer is quite correct to state that. Heterozygous as well as homozygous merles have been found to be associated with increased risk of eye and ear deformities in Dachshunds. Breeds that have a large expanse of white are probably at higher risk of hearing deformities though, in particular Great Danes where harlequin x harlequin breeding is not uncommon, I believe. Julie Vaughan

    Posted at 08:51 on 27 Nov 2009 by
    pod | Report as inappropriate

    8

    Julie I would be very interested to see the scientific evidence to back up that statement. That is certainly not the case in Border Collies where heterozygous merles are at no greater risk of being deaf or blind than any other colour.

    Posted at 10:41 on 27 Nov 2009 by
    Coires | Report as inappropriate

    9

    Willis referred to research papers in his 2005 article on merle. http://www.diademchihuahuas.50megs.com/about.html I'm pretty sure I've seen more recent reference to pleiotropic effects of heterozygous merle in other breeds. I'll report back if I find anything else.

    Posted at 15:35 on 27 Nov 2009 by
    pod | Report as inappropriate

    10

    Just a mention of one anomaly with the merle gene that will necessitate careful wording to prevent the breeding of homozygous merles. The merle allele, whether in single or double dose, requires eumelanin (dark - black or brown in the Dachshund) pigment to express. A red/cream coloured dog with little or no shading could easily carry the merle allele without showing any evidence of the merle pattern.... what's known as a cryptic merle. So to be certain, reds, sables and creams should also not be bred to merles, unless of course DNA tested for this gene.

    Posted at 16:35 on 27 Nov 2009 by
    pod | Report as inappropriate

    11

    Hmm interesting Julie, but back in 1977 when they did this research just how did they differentiate between MM (homozygous merle) and Mm (heterozygous merle)? Was it done phenotypically? Because they have only just identified the merle gene haven't they? If it was done on subsequent matings this is not a reliable measure because it is possible for a homozygous merle to produce non-merle offspring because the merle locus contains a transposable element. I sadly cannot read German well enough to spend my time searching for and reading the original articles to investigate the methodology, have you? As a scientist I do not like to accept other people's interpretation (even the 'great' Dr Malcolm Willis) and will always go back to original articles if at all possible. So this doesn't give me the 'evidence' I would like. Also I would like to know what they mean by 'slight hardness of hearing' and how they measured it, what equipment they used and also how they selected their control populations etc. Because that percentage seems awfully high. But I do agree with you Julie if there is any possibility of merle being present cryptically then one must not risk a double merle mating.

    Posted at 17:28 on 27 Nov 2009 by
    Coires | Report as inappropriate

    12

    A very interesting paper by George Strain et al (2009) here - http://www.lsu.edu/deafness/StrainMerleJVIM2009.pdf ... There are no positive conclusions drawn as the merle contribution to deafness in this study because of the presence of white spotting in some of the dogs. And a problem exist in attibuting white spotting to any particular gene as pigment distribution is not entirely under genetic control and merle itself also reduces pigment. Why the Dachshund studies are important... as a breed they don't have white markings. I haven't read the Dachshund studies either and yes I would agree with a problem differentiating between homozygous and heterozygous merles at that time, but only those from merle x merle breedings. All breedings of merle x non merle will produce heterozygous merle at a probability of 50% with no homozygotes possible. As individuals from this breeding are most likely to make up the bulk of the heterozygote dataset, there is not likely to be much room for error.

    Posted at 09:47 on 28 Nov 2009 by
    pod | Report as inappropriate

    13

    As long as their non-merle wasn't a cryptic merle LOL.

    Posted at 12:27 on 28 Nov 2009 by
    Coires | Report as inappropriate

    14

    Oops that went before I meant it to. I don't like to deal with 'most likely' and hope that nobody making any decisions that will affect the future of merles does either. All of the merles I have bred and owned have perfect hearing (BAER tested). So this claim of almost 40% heterozygous merles having some sort of undefined 'hardness of hearing' is very difficult to believe.

    Posted at 12:57 on 28 Nov 2009 by
    Coires | Report as inappropriate

    15

    By merle x non merle, I was referring to genotype rather phenotype :)

    Posted at 13:04 on 28 Nov 2009 by
    pod | Report as inappropriate

    16

    Rather THAN phenotype. Oh for an edit button! LOL

    Posted at 13:08 on 28 Nov 2009 by
    pod | Report as inappropriate

    17

    Just read the article Julie by Strain et al and as far as I can see they have no Control (non-merle) population! Why on earth they haven't done this I do not know, it is a fundamental requirement for all scientific studies. Unless you know what the deafness levels are in the wider population of the breeds in question the data is of absolutely no value, so interesting maybe but cannot be used as evidence against heterozygous merles as opposed to other colours, never mind whether excess white spotting was present or not. It makes me think they did do a control but found a higher incidence of deafness in the solids but as that is not newsworthy they kept it quiet?! And before you say it, there is no point in them referring to other studies quoting the levels of deafness, they should always do their own control to completely test their methodology against a background. They refer to a Platt et al study presumably from AHT where they also seem to have failed to genotype or differentiate between single/double merle and the heavily white dogs, so again, no conclusion there. Why does it seem to be so difficult for them to get it right?!

    Posted at 11:04 on 30 Nov 2009 by
    Coires | Report as inappropriate