Update: This research study is complete. Samples are no longer required.
>100 DNA samples needed for SCARF funded Bloat study
In 1987 the Morris Animal Foundation reported that there were approximately 60,000 cases of bloat in dogs in the USA with a mortality rate ranging from 7 -60 % depending on accessibility to adequate veterinary care. Clearly the understanding of this process at the molecular level and studies of the physiology of GDV are of importance to owners and breeders of purebred dogs.
Gastric dilatation - volvulus (GDV) is a life threatening condition and is found primarily in large to giant breeds. Most people know this condition as bloat. Although the exact cause of bloat is not known, it appears that this disorder may have multiple causes.
The genetics of bloat is probably complicated. An animal does not inherit bloat, but rather the predisposition to develop bloat.
Stress has been shown to be a risk factor. Recent kenneling or long car rides for example may cause many dogs to bloat. This research will focus on DNA sequencing genes known to be involved in the stress response.
DNA samples from a wide range of Samoyeds were used for this bloat research. Samples were requested from dogs who have bloated, their immediate relatives and normal samples from dogs who have not bloated and normal samples from dogs who have relatives that have bloated. Because the inheritance of this disorder appears to be complex, as many samples as possible were requested in order to show a statistical correlation of a mutation with the disease.
Participants were asked to enter their Samoyeds data in the SCARF DNA banking database, so that as much information as possible was collected on each animal. They were also required to collect DNA cheek swab samples, and sign a transfer of ownership document for the DNA submitted.
Thank you Dogenes and Samoyed owners for participating in this very important project!
Year end report on Bloat study
from Mary Whiteley, PhD
I am pleased to report that considerable progress has been made this year. Both of the candidate genes have now been DNA sequenced from a Collie that had GVD incident. I need to point out that these genes are very large. The issue at hand is now the analysis, and sequencing of appropriate control DNA. The analysis done so far has taken well over 100 hours. This entails searching the public domain DNA databases. The main problem with the canine genome in particular is that it was derived from a single Boxer, and therefore should not be considered to be the reference for all canine breeds. Since boxers also have a predisposition for bloat, this complicates any further research decisions. To get around this I compared the candidate genes with all other organisms, at both the DNA and protein levels. Several regions in both genes were identified as being unique to the dog. I am currently sequencing these regions from two control Samoyeds that are from a line that has been free of bloat for 10 generations as well as DNA samples from control breeds that are not known to have a predisposition for bloat. This should be completed over the next several months.
Note: I have data from DNA sequencing of other canine genes that shows that when the Boxer genome deviated from other species in critical regions of the gene/protein other canine breeds agreed with the consensus of the species.
What is critical to the success of this research is to collect a statistically significant number of clinical cases along with their relatives. Unfortunately I only have less than 10% of the goal of samples which need to be > 100. DNA samples from dogs from other bloat breeds are available, however because these genes are large it is possible that the mutations in these genes are in different regions of the genes. For example we know that the canine von Willebrands gene that is also large has a variety of mutations causing this bleeding disorder that are breed specific, but not conserved throughout.
Naturally if any of the analysis yields significant data I will inform all parties. Likewise if this does not show any promise, you will be informed.
I wish to thank you for all of your support and look forward to working with you in the future.
Mary H. Whiteley, PhD