Rocket & Copper

OptiGen - diagnostic lab service and information for genetic diseases in purebred dogs - canine genetic testing - Ithaca, New...


We can eradicate PRA in a short time if people will test their breeding parents before breeding.  A step that Lamars Mastiffs has already taken. LAMARS Mastiffs along with my  friend and "Trouble's " Owner Carrie Del Bonta are very proud to have been able to participate in this study.

Dominant PRA Test:

For: (Old English) Mastiff and Bullmastiff

Background information on this disease and on the research leading up to this genetic test is given on the Mastiff Club of America web site.

You can send in blood samples for testing by following the directions at the "Ship Sample" link and completing the "Request Test" form available at that link. The price of the Dominant PRA test for Mastiffs and Bullmastiffs is $120 per dog. The typical turn-around time from receipt of the blood sample to report of results is about 2 weeks.

Since vision loss might be recognized first when the dog is several years old, it’s important to determine the actual status of the dog before breeding it. The Mastiff Club of America (MCOA) states “PRA has been found during Mastiff eye exams as early as four months and there are Mastiffs that have CERFed as normal at three years and been found to have PRA before they turned four years old.” Since the same gene and mutation cause PRA in both (English) Mastiffs and Bullmastiffs, the same test is used for both. The Dominant PRA test for Mastiffs and Bullmastiffs detects the actual mutation in the PRA disease gene. The test can be done at any age – from pup to adult, including prior to any vision loss, and the result will never change with age.

Mastiffs and Bullmastiffs exhibit the first, and so far, only form of canine Progressive Retinal Atrophy – PRA - that is dominantly inherited. This means a single copy of the mutant gene causes the disease, in contrast to two copies required in a recessive disease. (Remember - one copy of every gene is passed to the offspring from the dam and one from the sire.) There are no “carriers” of dominant PRA; dogs are either normal or affected.

The OptiGen test results for Dominant PRA will be reported as follows:

Homozygous Normal – this dog is not and will not become affected with PRA. It has two normal PRA gene copies and will pass along only the normal gene to its offspring.

Heterozygous Affected – this dog is or will be affected with PRA. It has one dominant PRA mutant gene copy and one normal gene copy. On average, half of its offspring will receive the mutant gene copy and half of its offspring will receive the normal gene copy.

Homozygous Affected – this dog is or will be affected with PRA. It has two dominant PRA mutant gene copies and no normal gene copies. All of its offspring will receive the mutant gene causing PRA.

Testing gives breeders a new genetic advantage. Based on test results, disease can be prevented with certainty. In the case of dominant disease, the mutant gene can be eliminated rapidly. This requires exclusion of the affected dog from further breedings. The MCOA states at its web site “Mastiffs with PRA should not be bred.” That might seem to be an impossible solution for some breeders, but then the consequences must be considered. The following table gives the possible breeding combinations and their outcomes.

NOTE: N designates the Normal gene copy, D designates the Dominant Mutant gene copy

Expected results for breeding strategies using the

OptiGen mutation test for Mastiff and Bullmastiff Dominant PRA

Parent 1

Genotype Parent 2 Genotype



NN Heterozygous


ND Homozygous



Homozygous Normal

NN All Normal = NN 1/2 Normal = NN

1/2 Hetero. Affect. = ND All Hetero. Affect. = ND

Heterozygous Affected

ND 1/2 Normal = NN

1/2 Hetero. Affect. = ND

1/4 Normal = NN

1/2 Hetero. Affect. = ND

1/4 Homozyg. Affect. = DD 1/2 Hetero. Affect. = ND

1/2 Homozyg. Affect. = DD

Homozygous Affected

DD All Hetero. Affect. = ND

1/2 Hetero. Affect. = ND

1/2 Homozyg.Affect. = DD All Homozyg.Affect. = DD

The research leading to this discovery was undertaken by scientists at the James A. Baker Institute of Animal Health at Cornell University's College of Veterinary Medicine in Ithaca, New York, and published in volume 99 of the April 2002 issue of the Proceedings of the National Academy of Sciences. The technology underlying this test is done by agreement with Cornell Research Foundation, Inc. PCR technology is performed under a license agreement with Roche Molecular 

Updated March 16, 2001

What is a Meagle?

A Meagle is dog that is a mixed breed of 1/2 Old English Mastiff and 1/2 Beagle cross. Hence the name Meagle. The sire was a Beagle cross owned by the Retinal Disease Study Facility. He is a combination of 5/8 Beagle, 1/8 Poodle, 1/8 Husky, and 1/8 Irish Setter. The dam was a purebred Champion Mastiff owned by Carrie Del Bonta and Bred / co-owned by Margo Lauritsen. The sire is known not to carry any genes for PRA and the dam is PRA affected.

The STUDY breeding was sponsored by the Mastiff Club of America to determine the mode of inheritance of PRA in mastiffs and subsequently lead to a DNA test for the PRA gene.

The Six Meagles 12 -14-1999

Why did we do this breeding?

PRA is a degenerative disorder that eventually leads to blindness. PRA is often not recognized until a dog is over 2 years old thus creating a nightmare for breeders. What breeders needed was a way to determine if a dog had PRA before breeding them. Breeders needed a DNA test. A few concerned breeders got together and with the help of the Mastiff Club of America formed the PRA committee. Over the years the PRA committee has spread awareness about PRA to Mastiff owners and has led a campaign for Mastiff breeders to CERF their dogs before they breed them. With the outstanding support of the Mastiff community thousands of dollars have been raised for this research. Each year the M.C.O.A sponsors a PRA Walk to raise money for this worthy cause.

Meet the Parents.

Sire: H302 Dam: Ch. Lamar's Nut'n but Trouble

Note, Two of the Meagles (Murphy and Sabraina) were diagnosed with PRA. We are certain that PRA is a Positive gene and they have already developed a blood test to determine if your Mastiff has PRA. Please visit the following link and read about the test and test your dogs.