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June 2017
The past months the Scandinavian Ragdoll Club (SRC) have mapped and further analyzed the pedigrees of the for us known ragdoll kittens that have been born with dwarfism. Common to all the affected kittens is that they all have the cat Patriarca Gucci on both mother’s and fathers side of the pedigree. In some cases Gucci is as far away as 8-9 generations, and this distance will of course increase with time. Because of this, Gucci is not always visible at first glance and it is important that breeders really get to know their pedigrees when breeding plans are made. Gucci was born 2001-03-18, so you have to search that far back to find her in pedigrees.
The collected information and the mapping of the same is the foundation of the research project about dwarfism in ragdolls that the Swedish University of Agricultural Sciences (SLU) are working with right now. This project have also received financial support from SKKs and Agrias Research Fund for two years. SRC also have conversations with the health council of SVERAK (FIFé), and they have received our mapping during a personal meeting. At the time of writing we have knowledge of approximately 40 affected kittens, most of which have been registered in SVERAK. But SRC have been aware of some dwarfs born abroad as well. All of the affected kittens share the same genetic background.
Statistics from past breeding years
All litters registered in SVERAK are available online in FindUs. During the years of 2015 and 2016 a total of 80 matings were made where Gucci were duplicated, i.e. present on both the mothers and the fathers side in the pedigrees (as comparison a total of approximately 1050-1150 ragdoll litters were registered in SVERAK during this time). in 18 of these 80 litters one or more dwarfs were born. In percent that gives us an outcome of 22,5% that you would get an affected kitten in a litter were you duplicated Gucci. All of the statistics are retrieved from FindUs, and are calculated based on the number of affected kittens we have knowledge about today. We also know there might be a number of unrecorded dwarfs born that SRC does not know about.
Sorce: FindUs | Total number of litters with Gucci duplicated | Number of litters with known dwarfs | Percent affected litters |
|---|---|---|---|
Duplications 2015 | 33 | 7 | 21,2 % |
Duplications 2016 | 47 | 11 | 23,4 % |
Duplications in total 2015-2016 | 80 | 18 | 22,5 % |
Current low risk lines
During the mapping we have found three cats born of Seierø’s Prima Donna (Gucci’s daughter) whose lines have not produced any dwarf kittens that we know about today in Swedish catterys. This despite of being exposed to repeated matings with confirmed carriers and/or with carriers nearby in matings since 2010. The three cats are Hvenhildas Rufus, Hvenhildas Rakel and Hvenhildas Ulrik. Based on the information that are available today, SRC make the assessment that these three cats and their offsprings may pose a low risk for dwarfism in combinations where Gucci is duplicated. Please notice though that there are other active breeding lines in Sweden and abroad after Prima Donna that cannot be considered low risk lines.
Of the 80 duplicated combinations made 2015 and 2016 we mentioned earlier, 22 were made with one of these low risk lines on one or both sides of the parents linage. These combinations have to our knowledge not given any dwarf kittens at all. With these mating removed from the calculations, 58 (80-22=58) duplicated litters were born during these years, and they resulted in 18 litters where at least one ragdoll kitten was born with dwarfism. In percent that gives us an outcome of 31,0 % that you would get an affected kitten in a litter were you duplicated Gucci (low risk lines removed from calculations).
Sorce: FindUs | Total number of litters with Gucci duplicated | Number of litters with known dwarfs | Percent affected litters | Total number of litters with Gucci duplicated without "low risk lines" | Percent affected litters without "low risk lines" |
|---|---|---|---|---|---|
Duplications 2015 | 33 | 7 | 21,2 % | 27 | 25,9 % |
Duplications 2016 | 47 | 11 | 23,4 % | 31 | 35,5 % |
Duplications in total 2015-2016 | 80 | 18 | 22,5 % | 58 | 31,0 % |
Summary and breeding recommendations
Based on the results of the mapping our recommendation is still to not duplicate Gucci when breeding. We also recommend breeders to use common sense when working with the current low risk lines, and be aware that the information can be changed quickly if a dwarf kitten would be born in these lines as well. We also want to highlight the importance of doing combinations completely free from these lines if possible, to avoid adding the line to too many pedigrees, while we wait for information about the progress of a DNA-test.
To investigate which lines that could be considered a low risk for dwarfism is an important work to maintain genetic diversity in the long term perspective. This will be even more important if it turns out that we are unable to get a DNA-test. By cooperating and gather information we can find more lines that might be considered “safe” to use when breeding, without the risk of putting more dwarf kittens to life. All tips, ideas and thoughts are of value, and everything can be sent to us anonymously is desired. You can find the link to our tip form HERE.
Obviously, not all cats that have Gucci as an ancestor is automatically carriers of this gene for dwarfism. In recessive/co dominant inheritance there is a 50 % risk/chance that a gene will either be given to the offspring or not, for each generation. To determine if a cat might be considered having low risk of being a carrier you need to find combinations were the cat has been mated with known or nearby carriers several times. In some cases you need to follow the cat through several generations to be able to estimate the chance of being a carrier.
Finally..
Lastly we would like to thank you for all tips and information that has made this mapping and first overview of the situation possible.
Please continue to share your experiences and be open between other breeders. It’s in everyone’s interest to find out how the current situations is with carriers in the pedigrees of your breeding cats. Especially today when we do not have access to a DNA-test. The information that SRC have received from various channels have been sent provided that it would only be used in unidentified form. With this in mind we will not publicly share the names of affected kittens and their cattery names. Our assessment is that we are more likely to receive information if the provider of the information have the option to be anonymous.