Concern for the present and future genetic health of cat breeds has prompted breed organizations and
breeders to organize genetic diversity studies as a means to examine the genetic status of their breed of interest. Such studies involve comprehensive sampling of breeding cats from around the world that represent different lineages for each breed, and are designed to provide information useful for breed management. One project recently completed was for the Singapura cat. The Siamese Cat Genetic Diversity Project is organized by Rose Meekings (UK), vice-chairman of the Siamese Joint Advisory Committee of the Governing Council of the Cat Fancy (GCCF), who is responsible for organizing the DNA sampling process and sample submission to the Veterinary Genetics Laboratory (VGL), University of California, Davis, CA, USA, and by Dr. Cecilia Penedo who is responsible for testing, analyses, reports and scientific advising.
The objectives of the study are a) to analyse genetic variation for single nucleotide polymorphisms (SNPs) and microsatellites (STRs), phenotypic traits (color and hair length) and genetic defects present in the breed, and b) to provide information and recommendations to improve the genetic health of the breed. A central issue for many cat breeds concerns the impact of breed management versus outcrossing as a means to effect changes in the genetic make-up of the breed while maintaining phenotypic standards. The extensive genetic analyses proposed address these questions, provided that adequate numbers of cats are sampled from different geographic areas.
DNA sampling - DNA samples are obtained from buccal swabs submitted for testing to the Veterinary Genetics Laboratory, University of California, Davis, California, USA. Each sample received will receive a case number for tracking/reference purpose. All required vital data for each cat will be stored at the VGL database.
DNA Testing - Once all DNA samples are assembled they will be assayed for 148 SNPs, 34 STRs, 6 coat color genes (Agouti, Albino, MC1R, Brown, Colorpoint, Dilute) and 4 disease genes relevant to the breed (PKD, PRA1, MPS VI and MPSVII). The anonymous SNP and STR markers provide data for genetic diversity analysis. The coat color and disease testing provide information about phenotypic and genetic health status of the breed.
Genetic Analysis - Genetic variation for SNPs and STRs are assessed according to overall presence of allelic variants among loci screened (genetic diversity), average number of alleles, population inbreeding (Fis) and proportion of polymorphic loci for each individual (heterozygosity). Breed substructure and patterns of distribution of genetic variation is analyzed according to geographic grouping of samples and genetic distance among groups. Variation of phenotypic traits and genetic disease are summarized by observed allele frequencies.
Results - Results are presented in two forms: 1) as individual, private reports to owners/participants that contain information about animal heterozygosity and results for phenotypic and disease traits for each cat submitted to the study, and 2) project report containing global analyses of genetic diversity, findings and recommendations.
The global report is prepared for distribution by project organizer to all participants and also to breed clubs and registries.