Another contraversial topic in the Chihuahua World concerns the Merle Chihuahua which displays an unuasual coat for sure but comes with what has been proven  health problems after research found that Merle Gene dogs suffer with eye problems, sperm imperfections and hearing disorders. Chihuahua World DNA profiles any dogs we breed which screens for the Merle gene so would not breed from any adults found to be Merle Gene positive.


Below is an article that involved the Kennel Club after an interview on an ITV morning show a few years back:

Chihuahua row erupts after TV show

The popular daytime television show, Richard and Judy, is in trouble with Chihuahua breeders after interviewing a woman on Tuesday 17th June who advocated the breeding Chihuahuas carrying the merle dominant gene with a Dapple (merle) Dachshund which also carries the merle dominant gene. Apart from 'blatantly promoting designer dogs' says Sylvia Fresson, the breeder commented during the programme that such dogs (i.e. cross bred dogs) could be healthier than pure-bred dogs.

In her letter to the programme sent by recorded delivery, Sylvia said: 'I consider it thoroughly irresponsible of you to mislead the general public into believing that such "designer dog" breeding, in this particular case, is desirable, when it is in fact a disaster – heartache and expense for the owner and misery for the little animal involved. There are already dozens of puppy farmer/get-rich-quick dealers on the internet capitalising on such practices, without a presumably reputable association like yourselves condoning them. In fairness to your viewers you should put this right and highlight the health issues involved in your next programme'.

In 2007 Sylvia, a committee member of the West Country Chihuahua Club, chaired a meeting at the Kennel Club with the Kennel Club geneticist, Dr J Sampson and representatives of the various Chihuahua breed clubs, which led to the Kennel Club agreeing to ban the registration of merle Chihuahuas on health grounds and the Breed Standard was subsequently changed to exclude merle. At the time, the KC press release said: 'Coat colour in the Chihuahua is complex because a range of colours is acceptable, but one colour that does not exist naturally in the breed is Merle.'
Merle 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 being dominant to non-merle. 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.
Many breeds are aware of and have for many years dealt perfectly adequately with avoiding the consequences of these health issues. However, because the colour has not hitherto been encountered in the United Kingdom in Chihuahuas, and the fact that it is not a natural colour in the breed, the General Committee of the Kennel Club has decided as a precautionary move to take a different approach. At the suggestion of the majority of the Chihuahua breed clubs in this country, the Kennel Club has decided not to register merle (dapple) Chihuahuas (Smooth or Longcoat) in order to avoid any future possible problems.' Subsequently the breed standard was changed to read; 'Any colour or mixture of colours but never merle (dapple).'

Despite this, the KC has continued to register merle Chihuahuas because, they now say, that if the breeders states that 'merle' is the colour of the puppy they have to register it as such. Graham Foote, Chairman of the British Chihuahuas Club told Our Dogs: 'the Chihuahuas folk are very concerned about this refusal by the Kennel Club not to implement their agreement. It is our view that the 'merle' colours are being established in the country through American imports where puppy farmers are producing dogs designed to sell as being of unusual colour. As a result, one UK breeder is averaging over five puppies a litter many of which are described at 'merle'. No only is this damaging in itself but this is quite impossible in the breed where three is considered a goodly number. It is likely that this lady is using bigger bitches in her breeding programme which may not even be true Chihuahuas although they might have been imported or registered as such.

Leading canine geneticist Dr Malcolm Willis, author of Genetics of the Dog, wrote an article on the subject of merle Chihuahuas in 2005 which clearly demonstrates how dangerous merle to merle breeding is, whether between two different breeds of dog or within one breed. He wrote: 'Over thirty years ago researchers showed that merle Dachshunds tended to have eye problems, sperm imperfections and impaired hearing. These problems were found in homozygous merles and also heterozygous merles. Hearing faults ranging from complete deafness to slight hardness of hearing occurred in 54.6% of homozygous merles and 36.8%of heterozygous merles. Based on this work many geneticists have suggested restricting the breeding of merles on welfare grounds. In any event, merle is biologically dangerous and not like any other colour' and is conclusion is that 'merle to merle' breeding should never be contemplated.

Sylvia Fresson has not yet heard from the programme.


Many people will make their own minds up about these issues but if you are still not sure about the Merle Chihuahua Puppies we have found a couple of links that go into this subject in great depth: