Tag Archives: bulldog

Bulldogs’ Screw Tails Linked to Human Genetic Disease

With their small size, stubby faces and wide-set eyes, bulldogs, French bulldogs and Boston terriers are among the most popular of domestic dog breeds. Now researchers at the University of California, Davis, School of Veterinary Medicine have found the genetic basis for these dogs’ appearance, and linked it to a rare inherited syndrome in humans.

bulldog

Moxie, a 3-year-old French bulldog, took part in a study of the genetics of “screwtail” dog breeds (bulldogs, French bulldogs and Boston terriers). A common mutation in these dogs is similar to genetic changes in a rare human disease, Robinow syndrome. (Photo credit: Katy Robertson)

Bulldogs, French bulldogs and Boston terriers aren’t the only dogs with short, wide heads, but they do share another feature not found in other breeds: a short, kinked tail or “screwtail,” said Professor Danika Bannasch, Department of Population Health and Reproduction in the UC Davis School of Veterinary Medicine. These three breeds all lack the vertebrae that make up the tail bone, she said.

The researchers sequenced the whole genome — the entire DNA sequence — of 100 dogs, including 10 from screwtail breeds. All the participating dogs were privately owned pets seen at the UC Davis Veterinary Medical Teaching Hospital, whose owners agreed to participate. Graduate students Tamer Mansour and Katherine Lucot, with C. Titus Brown, associate professor at the School of Veterinary Medicine and Genome Center, searched through the DNA sequences to find changes associated with screwtail breeds.

From more than 12 million individual differences they were able to identify one mutation, in a gene called DISHEVELLED 2 or DVL2. This variant was found in 100 percent of the bulldogs and French bulldogs sampled, and was very common in Boston terriers.

This kind of whole genome comparison is relatively new, Bannasch said.

“Normally, we would have first had to identify a region DNA and work from there,” she said. “We could look at breed-specific traits, but not as well as we can now.”

Professor Henry Ho at the UC Davis School of Medicine studies similar genes in humans. Mutations in the related DVL1 and DVL3 genes are known to cause Robinow syndrome, a rare inherited disorder in humans characterized by strikingly similar anatomical changes — a short, wide “babyface,” short limbs and spinal deformities. In addition, Robinow patients and the screwtail breeds also share other disease traits, such as cleft palate. In both humans and dogs, DVL genes are part of a signaling pathway called WNT involved in development of the skeleton and nervous system, among other things, said Peter Dickinson, professor of surgical and radiological sciences at the School of Veterinary Medicine. By characterizing the screwtail DVL2 protein product, Sara Konopelski, a graduate student in the Ho lab, pinpointed a key biochemical step in the WNT pathway that is disrupted by the mutation. This finding further suggests that a common molecular defect is responsible for the distinct appearances of both Robinow patients and screwtail dog breeds.

The DVL2 screwtail mutation is so common in these breeds, and so closely tied to the breed appearance, that it would be difficult to remove it by breeding, Dickinson said. Other genes are known to contribute to short, wide “brachycephalic” heads in dogs, and there are likely multiple genes that contribute both to appearance and to chronic health problems in these breeds.

Understanding a common mutation in popular dog breeds may, however, give more insight into the rare Robinow syndrome in humans. Only a few hundred cases have been documented since the syndrome was identified in 1969.

“It’s a very rare human disease but very common in dogs, so that could be a model for the human syndrome,” Bannasch said.

Source:  UC Davis media release

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No simple way of predicting breathing difficulties in pugs, French bulldogs and bulldogs from external features

As many as a half of all short-nosed dogs such as pugs, French bulldogs and bulldogs experience breathing difficulties related to their facial structure. However, research published by the University of Cambridge suggests that there is no way to accurately predict from visible features whether an apparently healthy pug or French bulldog will go on to develop breathing difficulties.

The findings have implications for attempts to ‘breed out’ this potentially life-threatening condition.

French bulldog.jpg

Pugs and bulldogs have become popular breeds in recent years – the French bulldog is set to become the UK’s most popular canine, according to the Kennel Club. However, a significant proportion are affected by a condition known as Brachycephalic Obstructive Airway Syndrome (BOAS) related to their head structure.

Studies suggest that for over half of such dogs, BOAS may lead to health problems, causing not just snoring but also difficulty exercising and potentially overheating. It can even prove life-threating. But as symptoms often do not arise until after the dog has begun breeding, veterinary scientists have been searching for markers that can predict whether a dog is likely to develop breathing difficulties – and hence potentially help breed out the condition.

A study in 2015 led by researchers at the Royal Veterinary College, University of London, working across many breeds suggested that dogs whose muzzles comprised less than half their cranial lengths and dogs with thicker neck girths were at increased risk of BOAS. However, this new study suggests that these measures applied to individual breeds are not dependable for this purpose.

The Cambridge researchers took external measurements of features of head and neck shape, and of the external appearance of nostrils, together with measurements of body size and body condition score (an approximation to the degree of fatness/obesity) in just over 600 pugs, bulldogs and French bulldogs, the most numerous breeds that show this problem. Each of the dogs had also been graded objectively for respiratory function.

The team found that while the external head measurements did have some predictive value for respiratory function, the relationship was not strong, and the measurements that showed the best predictive relationship to BOAS differed between breeds. They were unable to reproduce conclusively the findings from the previous study by the Royal Veterinary College in any breed.

“It can be incredibly difficult to take measurements such as distance between eyes or length of nose accurately, even for experienced vets, as the dogs don’t keep still,” says Dr Jane Ladlow, joint lead author. “This may explain why it is so difficult to replicate the findings of the previous study or find any conclusive markers in our own.”

Neck girth was a slightly more reproducible measurement, and larger neck girth in comparison to chest girth or neck length was associated with disease in the bulldogs and French bulldogs. In male bulldogs, neck girth showed a close enough association with disease to give moderately good predictive accuracy for the presence of clinically significant BOAS.

The best measure identified by the Cambridge team was the degree of nostril opening, which proved a moderately good predictor of the presence and severity of BOAS in pugs and French bulldogs, and was also a useful marker for disease in bulldogs.

Altogether the variables measured, when combined, gave an 80% accuracy in predicting whether or not dogs will have BOAS, the difficulty of taking some of the measurements accurately, and the need to make multiple measurements and combine them in order to produce a prediction means that the researchers would not recommend using them as a guide to breeding.

Dr Nai-Chieh Liu, first author of the study, says: “Breeding for open nostrils is probably the best simple way to improve these breeds. Dog breeders should also avoid using dogs with extremely short muzzles, wide faces, and thick necks. These traits are all associated with increased risk of having BOAS.”

Joint lead author Dr David Sargan adds “At this moment there is no conclusive way of predicting whether any individual pug or bulldog will develop breathing difficulties, so we are now looking for genetic tests that may help breeders get rid of BOAS more rapidly.

“The best advice we can give to owners of short-nosed dogs is to make sure you get your dog checked annually for any potential difficulties in breathing, even if you have not yourself observed any in your dog, and to keep your dog fit and not let it get fat.”

Source:  University of Cambridge media release

Best dogs for apartment living

Did you know that the American Kennel Club has published a list of the best dogs for apartment living?

With cities growing and land prices escalating, most metropolitan areas around the globe are looking to establish neighborhoods characterized by apartments rather than single-family homes.  This move can create challenges for people wanting to ensure that dogs remain part of their lives.

Years ago for example, in New  Zealand, the main telecommunications company here used a Jack Russell Terrier named Spot in its commercials.  The breeding and demand for these dogs soared.  People thought that the dog, being small, would be good for the suburbs (let alone, apartments).  But terriers need wide-open spaces and are bred for hunting down prey like rabbits and ferrets.  The result:  lots of ill-behaved dogs and owners who were out of their depth.

I would say that this list is a starting point, many mixed-breed dogs can acclimate to apartment living with the right routine and devotion.  And small dog breeds need to be managed carefully around stairs – because a lifetime of walking up and down stairs puts a lot of strain on the back and shoulders….

The best dog breeds for apartment living are:

The Cavalier King Charles Spaniel

The Cavalier King Charles Spaniel

The Pug

The Pug

The Shih Tzu

The Shih Tzu

The Bulldog

The Bulldog

The Bichon Frise

The Bichon Frise

The French Bulldog

The French Bulldog

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The Greyhound

The Chinese Crested

The Chinese Crested

The Havanese

The Havanese

The Maltese

The Maltese

Kathleen Crisley, specialist in dog massage, rehabilitation and nutrition/food therapy, Canine Catering Ltd, Christchurch, New Zealand

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Wordless Wednesday, part 10

Bulldog in purple fleece

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Wordless Wednesday, part 4

Boston Red Sox dog

Getting your head around dog genetics

Another public release of research this week.  This one from the Genetics Society of America about an article entitled ‘The Genetics of Canine Skull Shape Variation.’  Published in the February issue of Genetics, researchers review progress in defining genes and pathways that determine dog skull shape and development.

The researchers believe that the results are useful to humans because of the genetic expression of the features is likely to be similar process in humans as in dogs.

Skull shape is a complex trait, involving multiple genes and their interactions. Thanks to standardized canine breeding, which documents more than 400 breeds worldwide, and their distinct morphological features, researchers can disentangle traits such as skull shape, which in many breeds is a breed-defining variation.

Researchers are beginning to identify which genes cause a Bulldog or a Pug to have short pushed-in faces, or brachycephaly, and those that cause Salukis or collies to have narrow, elongated snouts, or dolichocephaly.

Source:  Genetics Society of America media release

Alma mater dogs – The Yale University Bulldog

Yale University in New Haven, Connecticut is reportedly the first university in the United States to adopt a mascot, dating back to the 1890’s when a student from England started the tradition.

The official bulldog is named ‘Handsome Dan’ and the university’s current Handsome Dan is Number 17!  (You can read about all of the Handsome Dans on this website.)

Handsome Dan will appear at games of the university’s football team – you guessed it – The Bulldogs.

Cole Porter (class of 1913) wrote the Bulldog Song, which is the Yale fight song.  It’s played by the band whenever a touchdown is scored.  The song goes like this:

Bulldog!  Bulldog!
Bow, wow, wow
Eli Yale
Bulldog!  Bulldog!
Bow, wow, wow
Our team can never fail

When the sons of Eli
Break through the line
That is the sign we hail
Bulldog!  Bulldog!
Bow, wow, wow
Eli Yale!

Official merchandise of the Yale athletics teams is known as Bulldog Blue.

And like most university mascots, the image of Handsome Dan is replicated throughout merchandise, events and student life on the Yale campus.