5th August 2007, 06:53 PM
DNA research question?
I have been following the sites about Cavaliers and SM. I understand the research takes time, and concrete dates cannot be given, but does anyone have a ballpark idea of when a DNA test may be available for SM, or even MVD. Are we looking at 5 years, 10 years, or longer?
Patience is not my greatest virtue.
6th August 2007, 03:20 AM
Researchers don't think it would be before 5 years, maybe 10. One problem is that it took much longer than it should have to get the basic samples to start the scan for the international project. Many breeders only submitted partial information or withheld information fter submitting data initially which meant it took much longer and additional scans, to have the broad sample needed and also to have the affected and unaffected dogs of other breeds as controls. There has also been little support for funding. Breeders really need to be pressuring clubs to back this type of research if they want results sooner rather thn many, many years down the line (so much more could be done, and so uch faster, with even basic research funding!). It really has been down to individual donations -- for example board members here and elsewhere recently raised funds so that a single needed scan could be done for this exact research. To me, it is nothing short of scandalous that such funding has to be raised in such piecemeal ways at this late point. Researchers have been very, very grateful that at least, individual breeders and pet owners, and some clubs, have shown a willingness to try to make this research happen.
Inheritence looks to be so complex that as far as I currently understand, it is unlikely breeding will ever be able to simply involve a single DNA test for SM. Instead such a test would become one of a range of tools breeders could use to assess a given dog's suitablity for breeding without providing any definitive answers.
The goal of the DNA research is to understand inheritence and perhaps identify more at risk lines. A DNA test would be a possible development but is not definite.
As with MVD the best way forward at this time, in the view of the majority of key reserchers in the area, is to try to limit severity by following the recommended breeding guidelines, MRI all breeding animals, and form breeding decisions on the basis of affectedness. This is what is done with MVD (except auscultation is done rather than MRIs) as inheritence is not understood, and there's no genetic test for the condition, either. It's pretty clear though that breeding affected, young dogs rather than unaffected dogs or dogs that remain unaffected til after age 5 raises the risk of early onset heart problems. There doesn't seem much chance of eliminating the genes, as the genes for MVD seem to be widespread, as the genes for SM are presumed to be.
Clare Rusbridge has pointed out that most of the old clear lines and dogs are long gone now so research asap is so essential if more of the remaining clearer lines don't disappear too. It is a race against time, and delays to important research such as the genome scan mean fewer and fewer options will remain for rescuing the breed.
BTW the genome scan was intended to include MVD as well as DNA but as some breeders failed to provide needed heart information this was unable to proceed. There is some hope it could still be included or maybe a new project will be undertake but this seems such a waste -- this research, so badly needed, could be well underway by now if breeders would cooperate on a broader level.
In memory: Lucy
Cavalier SM Infosite:www.smcavaliers.com
6th August 2007, 04:07 AM
Thank you Karlin for the information and explanation. I have a goal to eventually show and breed Cavaliers. I adore the one I own, but an acquaintance has a young sweetie with SM, and it is frightening to think of producing afflicted pups.
I have been researching and learning about this breed now for a couple of years. I am as well aghast at the lack of concern I see from many breeders about following the MVD protocol, and many are just silent about SM.
One breeder I email has just announced to me she is doing a brother/sister pairing next year, this inspite of the recommendation to avoid this close a breeding by Clare Rusbridge due to SM. She is just very confident in her chosen line.
My husband wants me to wait ten years before I venture into breeding anyway. Hopefully the breed will still be viable.
6th August 2007, 06:43 AM
6th August 2007, 04:38 PM
My jaw was on the floor when I received that email from that breeder.
She has a gorgeous website with tons of information on her pedigrees and her accomplishments in showing, and as well forth coming about the health problems in this breed. Her dogs are gorgeous and I had emailed in regards to perhaps looking at a puppy from her younger female in the next year or two for showing. In the reply she announced she was doing the pairing to set her line. I looked at the website, and they are half brother and sister, but I was still flabberghasted. I am well aware that this is too close and thought that any Cavalier breeder would think so too.
I do post regularly on Dogster.com about Cavaliers and the wonderful dogs they are, but as well about their health problems. I am hoping to bring awareness to even a few more about SM and MVD .
Again, Karlin, thanks for the insight.