GENETIC DIVERSITY STUDY IN SIAMESE
Proposal: To set up a project to investigate the Genetic Diversity (abbreviated to GD hereinafter) of GCCF Registered Siamese. This will involve working with the Veterinary Genetics Laboratory (VGL) at UC Davis(UCD) in collecting DNA samples to be used as part of a project comparing cats of the same breed from different countries. It is being undertaken with the full knowledge of the Siamese Cat Joint Advisory Committee (SCJAC) and the Genetics Committee of the GCCF.
Control Groups, each with the results of about 20 cats, will be set up for each country. These will then be used to
calculate the average GD for the Siamese of that country. Individuals selected should ideally be unrelated (no parent
or offspring included from any contributor) and belonging to a current breeding programme whenever possible. All
cats will be screened with DNA markers for diversity, relevant cat genetic diseases for which VGL have tests
available, coat colour and hair length traits. Individual animals will be ranked according to diversity (high to low) and
potential disease carriers identified. Results are then issued to the owner of each cat and these can then be used by
breeders to evaluate their individual future breeding programmes.
NB It is the intention that the findings from this study should be shared with the other participating parties.
Funding the Proposal: The tests of the 20 cats to be used as the GCCF Control Group are being funded by donations
from the Siamese Cat Clubs. This money is being kept separate and not used for any other purpose. Any surplus
money will be refunded to the clubs pro rata.
VGL have offered a special rate for the tests at $90 per cat (a bit less than £60 at the current exchange rate). Any additional tests required should be paid for by the owners of the cats concerned, again at $90, whilst the project is in progress.
Background Concept: GD, the level of biodiversity, refers to the total number of genetic characteristics in the genetic makeup of a species. It is distinct from genetic variability which describes the tendency of those genetic characteristics to vary.
The paper by Lipinski et al. (2008) 'The Ascent of Cat Breeds' , determined the genetic relationships of cat breeds, their geographical origins and the levels of genetic loss due to inbreeding. It was found that cat breeds had overall less GD than random-bred cats although this loss did not correlate with either popularity or age of the breed. Over 20 deleterious genetic disorders have been recognised in modern cats and all have been identified in pure breeds. This study thus provides a warning to modern cat fanciers that breed development must be done slowly and with the maintenance of a broad genetic base. The Cat Ancestry Test now being offered by UCD  has been developed as a result of this work.
Justification: The study that is being proposed would be very valuable in producing a method which breeders will be able to use in the future to monitor the outcome of their breeding programmes. Traditionally Inbreeding Coefficients have been used as a measure of the genetic health of a cat but this method has its limitations. Calculations depend on the number of common ancestors on the fatherís and motherís pedigrees where a high figure will be an indication of too close breeding but a low figure may be misleading as the result is only as good as the pedigree information available. This means that it is possible to have a pedigree which looks very out-crossed, but which has only a few cats a long way back.
At the World Cat Congress (WCC) Seminar 2013 Professor Sir Patrick Bateson FRS gave a lecture on the Welfare Aspects of Breeding Cats. He stated that the outcome of inbreeding can be serious with possible loss of vigour, consequential health problems and fertility and reproduction issues, with both congenital and genetic disorders more likely to be expressed. It was his opinion that our pedigree cats are far more inbred than currently suggested as this belief was based on the assumption that the population is of infinite size and that previous mating had been random within it . This clearly is not the case. Indeed there is a limit to the extent of our knowledge about the Siamese, a breed that has been in existence for over 100 years but had a very low number of foundation cats. Furthermore it must be remembered that there was a significant population bottleneck in the UK (sharp reduction of size of the population) due to the intervention of both World Wars which will undoubtedly have affected the GD.
Comments made by the Genetics Committee on the Siamese Breeding Policy included the suggestion that the Siamese Breed has a low GD and recommended considering outcrosses to another breed or for allowing imported Siamese from Thailand. The figures used to justify this were derived from the same study by UCD (Lipinski et al (2008)) already mentioned . Since these cats were CFA/TICA registered and have very different histories & registration policies from GCCF Siamese, in order to make any future recommendations a measure of the GD of GCCF registered cats is still required.
Please email Rosie Meekings if you wish to offer a possible candidate Siamese for testing or have
any questions that you would like answered. Cats should be from within a current Siamese breeding programme ie.
entire males or females and be at least a year old. A 6-generation pedigree is required. Siamese may be pure bred or
have Orientals or Foreign White cats within 6-generations. It is very important that all types of Siamese, from
Traditional to Show Cats, are included.
It is free of charge to any breeder whose candidate Siamese is accepted into the study.
 Geonomics (2008) 91(1):12-21. The ascent of cat breeds: genetic evaluations of breeds and worldwide randombred populations. Lipinski, MJ et al.
Cat Ancestry - Tracing the Lineage of Your Feline
WCC Seminar Report May 2013 Jen Lacey