good news on the gene marker front!
With some of the more worrying statistics about the percentages of cavaliers that seem to have SM and the malformation, this bit of fantastic news deserves some highlighting. I understand this to mean that the researchers have decided that from the DNA they have examined, they believe it will be possible to find a genetic marker for SM.
But better yet, that it won't be necessary to find an exact marker because given the information they already have, they believe there will be enough indications of the probability that a cavalier has the likelihood of having or passing along SM. That means people could do a sinple DNA test without needing a very expensive MRI, and also that it should be possible to start predicting which dogs have a higher likelihood of passing along more serious forms of SM. I'm hoping I am understanding all of that right! It will be kind of cool to have a cavalier genome too!
Marie Pierre Dube has completed a preliminary analysis of the initial scan and the good news is that the chosen markers are sufficiently informative enough to justify a whole genome scan in the CKCS breed. This first stage of gene mapping will involve around 500 markers and 200 dogs. Marie Pierre, a genetics epidemiologist, has recently taken on a position at the Montreal Heart Institute where she heads a research team in genetics of cardiology. She has a particular interest in MVD.
Zoha Kibar has been appointed as the molecular geneticist in charge of fine mapping and identification of the gene(s) defective in SM in the CKCS breed. Zoha pursued her postdoctoral studies at McGill University working on a mouse model for neural tube defects (NTDs) in humans. She is interested in identification and characterization of the molecular basis of congenital malformations of the central nervous system, particularly NTDs and Chiari malformations and she is planning to pursue her career as an independent researcher in this field.
She says: â€Genetic analysis is more definitive and accurate and of course cheaper than MRI. I have to stress the fact that we don't need to wait for identification of the gene for genotyping the dogs. Once we map the gene to a genomic region, we can select a few informative polymorphic markers that are tightly linked to the segregating phenotype (and hence the gene) and we can develop a genetic test that will give a probability value of carrying the defective gene. Of course identification of the gene and the underlying mutation will give a more clear-cut answer where sequencing the DNA will give a definitive genotype.â€