Simon Petersen-Jones & Lexi Mentzer
Michigan State University
Date: January 2007
DNA Samples: Thus far, we have 372 DNA samples from Cairn Terriers, of which 112 are from dogs affected with Ocular Melanosis. Currently we seem to not be collecting many blood samples outside of OM screening clinics, which might indicate that people think we have enough DNA samples. This is far from true! Without more samples, our pedigree and gene analysis cannot progress. Since our last report, the majority of the 61 new samples have come from early age examinations done by Ocular melanosis screening clinics around the country. Since we have recognized the need to start screening for OM in young dogs, we have increased the DNA stores of dogs not recognized to have OM because of the late onset of the disease. Please keep in mind that this puts even more emphasis on the need to recheck the dogs as they age, and to keep our records up to date with their ophthalmic exam report.
Since the November 2005 report, we have received 3 additional enucleated eyes, which have successfully been used in a melanocyte culture. This is the first step towards isolating the cells specific to the disease for further study.
Gene mapping project
Late in the Fall of 2006 we sent 69 more DNA samples to the Veterinary Genomics Laboratory at UC Davis from Cairn terriers. These samples were to accompany the initial 94 DNA samples sent in the spring of 2005 for genotyping using a microsatellite. We are currently in the process of analyzing the data collected from those samples to try and detect linkage of a portion of a chromosome with disease status. These new samples should be through the microsatellite and allele scoring process soon, and our laboratory will add the analysis of this sample population to our data to increase the numbers and add weight for the statistical applications.
Culture of abnormal cells from ocular melanosis
More affected eyes are needed for our work to isolate the cells causing disease by growing and separating them from other cells of the eye in our laboratory. It is important that these eyes are handled in a special way, so if you are in a position to donate to this cause, we will need to contact your veterinarian in advance. Recently we have had good success receiving eyes promptly from veterinarians interested in our research. A special thanks is due to the owners of these dogs for their dedication to our cause during times of emotional stress.
What we need
1. We ALWAYS need blood samples to use for DNA extraction from affected and related Cairns, accompanied by pedigrees and details of eye examinations. If your dog has not been sampled for our database, contact our lab to find out how easy it is to register.
2. We need enucleated eyes from dogs with OM. It is important that we are contacted before they are removed so that we can ensure that the eye is handled in an appropriate manner for the part of the project we intend to use the eye for.