Post on 16-Oct-2021
Genetics of BurmeseLeslie A. Lyons, PhD
Lalyons@ucdavis.edu
Associate ProfessorPopulation Health & Reproduction
School of Veterinary MedicineUniversity of California, Davis
Burmese Populations
• Traditional• Contemporary• European • Other registries• Color varieties 400 vs. 1400
Burmese Health Concerns• Hypokalemia• Diabetes• Flat-chest• FIP• Craniofacial Defect• Conditions associated with short
head structure (Cherry eye)• Others?• Declining population
What can be done?
• Improve genetic diversity!– Low genetic diversity is associated with
health issues
– Populations can suddenly go extinct
How to diversify?• Actively share blood lines
• Use other registries
• Cats of other breeds– Bombay, Singapura, Tonkinese,
European Burmese
• Southeast Asian cats
Cat Origins and Dispersal: Results
Bayesian clustering – STRUCTURE analysisRandombred cats
Cat Origins and Dispersal:Results
Distinctness of breeds – results of Bayesian clustering analysis
Burmese Colors
Domestic cat Agouti
Agouti, A- Non-agouti, aa (solid or self)
Eizirik et al.
Brown Locusallelic series: B > b > bl
B = blackb = brown (a.k.a. chocolate or chestnut) bl = light brown (cinnamon or red)
B - bb or bbl blbl
Mamm Genome. 2005 May;16(5):356-66.
Temperative-Sensitive Color
CCcscb
cscs
cbcb
Full Color Siamese or “Pointed”
Tonkinese
Burmese
Cat dilution• Simple recessive, 2 allele system (D, d)
Blue British Shorthair Russian Blue Korat
Fixed traits
Coat Color Genes for the Cat
• Agouti: A, a recessive solid• Black: B, b, bl recessive brown• Color: C, cb, cs co-dominant/rec points• Dilute: D, d recessive blue/grey• Inhibitor: I, i Dominant silver• Long fur: L, l Recessive long• Orange: O, o X-linked red/ginger• Spotting: S, s Dominant white spots• Tabby: Ta, Tm, Ts, tb Allelic series markings• White: W, w Dominant Full white
Known mutations, developing tests, linkages
Burmese Head Defect
How soon to the test?
• I hate this question!
• We know the right chromosome
• We know the right refined area
• We are now testing genes– 3 technicians focusing on the project
Once a FHD test, then• Do not breed carrier to carrier
– Requires continued genetic testing– If parents clear, then just need parentage test to
prove
• Slowly reduce frequency of FHD mutation over time
• Some may eliminate immediately, some not at all, this is OK!!!
Hypokalemia• Low potassium• Recurrent episodes of limb muscle
weakness & neck ventroflexion• Hyperkalemia mutation in other species
– Gene & mutation likely eliminated• Increased creatine kinase concentrations• Autosomal recessive
– May have incomplete penetrance– Tijdschr Diergeneeskd. 1998 Jul 15-Aug 1;123(14-15):435-7.
Hypokalemia Project
• Collaboration with UK, Germany, & USA
• All sharing samples
• Need to build pedigrees
• Need diagnostics also
Feline Infectious Peritonitis (FIP)
• Primarily a disease of younger cats originating from shelters or catteries Environmental effects
• Incidence among high risk group can be as high as 5% and mortality <95% High risk breeds?
• Two clinical forms – effusive (wet), and non-effusive (dry) Perhaps 2 genetic studies!
Feline Genome Sequencing
NIH supported 2X sequence completed
Broad Institute & AgenCourt
7X planned planned Washington University To start January 2009
Complex Disease Studies• Require a DNA source
– Consent form
• Good diagnostics– VMTH– Cat Specialists
• Case – controls samples
Cat PHIR Signalment
Cat PHIR Health Phenotypes
Action Plans• Breed census
– Number of breeders, breeding cats– Activate retired, ask for help– Implement the health survey
• Cohesive pedigree database– Parentage test cats– Use breeding programs to suggest mates
and reduce inbreeding (less emotion)
• Color test cats
Action Plans• Request outcross program
– Must actively use outcross
• Import one cat per year – Thailand, Other Burmese, other breeds– Health, type & color risks
• Remove breeder barriers
Acknowledgements
Feline Genetics Funding NIH – NCRR R24 Winn Feline Foundation Waltham Foundation Royal Canin UC Davis CCAH Cat breeders & private donors