Genetics Flashcards
______________ traits have a MORE predictable inheritance.
single-gene
T/F: Very few traits are controlled by single genes and several other factors play a role in determining the final phenotype.
true
___________ is a term that describes symptoms, which may or may not be present in a dog with an at-risk or affected genotype. The dog has the mutated gene in the right number of copies to cause the disease, but the dog may not show physical symptoms of the disease. In other words, the gene may not have an impact on the individual unless certain environmental factors occur.
Incomplete penetrance
________ includes dogs with the mutation in the right number of copies to produce the disease.
At risk
T/F: you only need one copy of an autosomal dominant gene in order to express disease/trait
true
___________ is the proportion of dogs with a particular genetic variant (or gene mutation) who exhibit signs and symptoms of a genetic disorder aka express the phenotype.
penetrance
Why are both males and females equally affected by autosomal dominant traits?
because the gene is located on a non-sex linked chromosome.
these are rare in vet med.
What are 2 examples of autosomal dominants genes in vet med?
- polycystic kidney disease in persian cats
- progressive rod/cone degeneration/atrophy in english mastiffs and bull mastiffs
We in encounter autosomal recessive genes much more commonly in vet med. How many copies of the affected genes are required to express disease?
2
carrier = one mutant, one normal
affected = mutant, mutant
what are 2 examples of an autosomal recessive disease in vet med?
- congenital myasthenia gravis of smooth fox terries
- PRCD
If you breed a mutant/normal to a mutant/normal, what percentage of offspring will be AFFECTED by the autosomal recessive gene?
25% affected (mutant, mutant)
50% carriers
25% normal
What breed pairing would create 100% carriers of an autosomal recessive disease?
normal individual (normal, normal) bred to a affected individual (mutant, mutant)
Which breeding pairing would result in 50% affected offspring and 50% carrier offspring for an autosomal recessive disease?
carrier individual (mutant, normal) bred to an affected individual (mutant, mutant)
what is an example of complete penetrance in vet med?
myasthenia gravis of smooth fox terriers
100% of individuals with the affected genotype will have the disease / express the phenotype.
what are 2 examples of incomplete penetrance in vet med?
- hereditary cataracts of aussies
- Von willebrands disease in dobermans
only SOME individuals with the affected genotype will express the disease / phenotype.
