Archives for May 2015

Preventing Inherited Ataxias and Primary Lens Luxation in the Parson Russell Terrier and Related Breeds

Preventing Inherited Ataxias and Primary Lens Luxation in the Parson Russell Terrier and Related Breeds

Previously known as the Jack Russell terrier, the Parson Russell terrier’s nearly 200 year long history began in the 1800’s when Parson John Russell of England obtained a terrier named Scout with the purpose of training him for European red fox hunting. Russell eventually developed a particularly adept line of terriers meant to run alongside hunters on horseback and dispatch foxes.

The name, Jack Russell Terrier was previously used to encompass dogs which are now recognized as three separate breeds in the U.S, the Jack Russell terrier, the Parson Russell terrier, and the Russell terrier. Despite their close genetic relationship and very similar appearance, leg length and body shape can be used to help differentiate the three breeds. Parson Russell terriers possess the longest legs and a square-shaped body while the other two breeds display shorter legs and a rectangular body shape. The Russell terrier is the shortest of the three varieties. Parson Russell terriers and Russell terriers are both recognized by the AKC, however the Jack Russell Terrier remains unrecognized by the organization and is bred primarily for its ability to hunt rather than for its conformational merits. Despite these physical differences, the three breeds share many genetic similarities ...

Preventing Hereditary Cataracts in the French Bulldog

Preventing Hereditary Cataracts in the French Bulldog

Though there are mysteries in regards to the early origins of the French bulldog, it is probable that this spunky breed is a 19th century product of breeding early English bulldogs and miniature bulldogs with other small breeds. As these smaller, English bred bulldogs became popular, many were either exported to France from England or accompanied their English owners to France in search of employment. At some point in the mid to late 1800’s, the small bulldogs were given the name “Bouledogue Français” and were recognized as their own unique breed. Early French bulldogs with either “rose ears” (ears folded at the tip) or pricked “bat ears” were common. However, with the spread of the breed to the United States, American dog fanciers created the first French bulldog breed standard describing the “bat ear” trait seen in modern Frenchies as the “correct” ear type.  In the process of establishing their modern appearance and perfecting the breed, like other purebred dogs, French bulldogs have developed some inherited diseases that concern Frenchie aficionados today. One such disease is a disorder known as hereditary cataracts (HC).

A cataract, in general, is the clouding of the lens of the eye. This cloudiness interferes ...

Preventable Inherited Eye Diseases of the Chinese Crested

Preventable Inherited Eye Diseases of the Chinese Crested

Despite being one of the most recognizable dog breeds in existence due to their unique physical attributes, the early history of the Chinese crested is a bit mysterious due to a lack of adequate written records. Though early hairless dogs have been documented in Africa, Central and South America, and Asia, the relationship between these dogs is not well understood. Evidence to suggest that they may be related is found in the fact that at least 3 hairless breeds originating from different continents (Mexican hairless, Peruvian hairless, and Chinese crested) are all known to inherit the same FOXI3 gene mutation responsible for their hairlessness. It is most likely that a common ancestor to the hairless breeds developed a spontaneous FOXI3 mutation that was later passed to the individual breeds as they were developed. It is theorized that early hairless dogs travelling on shipping routes with their human companions played a role in the spread of the trait to numerous locations in the world.

In addition to genetic mutations responsible for particular physical traits, like other purebred dogs, Chinese cresteds are known to inherit some genetic mutations responsible for causing inherited disease. Inherited diseases of the eyes are of particular concern ...