Population Genetic Health Handout Flashcards
Yakut horses
arrive in Siberia about 800 years ago and they have selective sweeps for
PRKG1 (shivering)
TGM3 (hair)
BARX2 (hair)
Fischer’s Fundamental theorem of natural selection
Adaptation/ improvement= selection + variation
(rate of adaptation/ improvement is proportional both the strength of selection and amount of variation in the population)
what is an animal breed
animals with homogenous behavior, characteristic and appearance
primary genetic risk to a breed
loss of genetic diversity (idea of wanting animals to breed through is at odds with idea of wanting animals to survive into future; end up with small effective population size and in turn no longer have viable and adaptable population
primary goal of genetic testing
prevention of inherited disorders
PWD carrier breeding
PWD had carrier frequency of 16% for GM1-gangliosidosis; bred from line free of this and ended up with 35% carrier frequency of prcd-PRA
Should you breed carriers
if carrier frequency is >1% breed carriers just not to each other (genetic test should make you not breed a good animal should just make you aware of who you choose to breed it too)
if you take too many dogs out or breeding pool you make v small effective population size and increase drift and create a bottle neck which in turn can lead to fixing of other deleterious alleles that you won’t have a test for so don’t do this
population management
having clinicians educate breeders through the process of decision making rather than letting them blindingly choose what to do on fb
Clinical role
clinical finding -> genetic mapping -> marker test -> marker assisted selection -> medial genetic counseling -> population management
breeder decisions
if health is number one conformation will suffer and visa versa; breeders decide who mates in in turn determine the selection that will be applied to the population
breeder definition
people who make reproductive decisions for animals; they decide what dx alleles get selected against
Rules of genetic testing
- Avoid selection for extreme phenotypes
- Use genetic tests to select healthy breeding animals
- Be wiling to modify breeding practices
Avoid selection for extreme phenotypes
extreem phenotypes will generally lead to health issues
ex bull dogs went through bottle neck and now we have disasters that get bred for more exaggerated traits; breeders are doing genetic tests for coat colors in bull dogs -> even less genetic diversity because people are dumb
Use genetic testing to select healthy breeding animals
- get rid of stigma around testing having dx in lines is normal need stigma to be in not testing
- breed quality carriers to normal testing individuals or keep detailed pedigree records to asses carrier risk if no genetic test; can also use linkage based tests
3 ways to reduce disease allele prevalence
- Genetic testing of parents
- Phenotypic testing of parents
- Pedigree analysis
linkage-marker based genetic tests
start with GWAS the compare test results to family members linkage based test in absence of GWAS; in linkage based test need to see how predictive test was in line in past if it wasn’t predictive don’t use it to make breeding decision
Choosing appropriate genetic tests
- must be scientifically soulnd
- must know if mutations relevant to that breed (degenerative myelopathy in boxer)
degenerative myelopathy in boxer
All DM dogs are homozygous but not all homozygotes get DM in boxers 43% homozygous for risk allele only .5% get DM; degenerative myelopathy is SOD1 test
Choosing genetic test
- breed clubs can advise
- are tests accepted by OFA (Orthepedic Foundation of Animals)
Genetic registries
databases of tested animals and pedigrees
- canine eye registry foundation (CREF)
- orthopedic foundation for animals (OFA)
- Canine health information center (CHIC)
- Feline Advisory Bureau (FAB-UK)
- need to keep track of inbreeding as well its ok to not be totally outcrossed if have good line but don’t want too much inbreeding either
breed clubs role in population genetic health
- take regular (anonymous) breed health surveys
- Work with CHIC, Kennel club ect. to determine genetic testing requirements/ recomendations
- Update breed standards when needed
- Counsel breeders and judges to select against traits that promote dx
- Fund breed- related genetic dx research
- Scientifically monitor whether loss genetic diversity impacting health, and implement controlled crossbreeding or even opening of studbooks if need to increase diversity
Team approach to genetic dx
- breeder and owner- make animal and population health the top priority
- Vets- clinical care of individuals and population
- Parent clubs and registration bodies (require good breeding practices, enforce policies)
- Geneticists and epidemiologists (foster population level mindset (do survelinece of population health, consult other stakeholders on good management practices for healthy populations)
stakes holder in genetic health of domestic animals
- pet owners
- Breeders
- Breed registries
- Vets
- Geneticists
