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