Estimating Risk of Inherited Genetic Disease Flashcards
What is meant by fitness?
The relative ability of organisms to survive and pass on genes
What is an allele that increases fitness?
Advantageous allele
What is a neutral allele?
Doesn’t effect fitness
What is a deleterios allele?
A decrease in fitness
What affects the health of the population?
The frequency of alleles
Do dominant alleles become more common from generation to generation?
No, relative frequencies remain constant
genotype frequencies also remain constant
What are the assumptions underlying the HWE? “Hardy Weinberg equilibrium”
- Mutation can be ignored
- Migration is negligible (No gene flow)
- Mating is random
- No selective pressure
- Population size is large
- Allele frequencies are equal in the sexes
What does the introduction of new alleles as a result of migration or intermarriage leads to?
New gene frequency in hybrid population.
What is the result of non-random mating?
Leads to increase mutant alleles, thereby increasing proportion of affected homozygotes
What is the choosing of partners due to shared characteristics?
Assortative Mating
What is Consanguinity
Marriage between close blood relatives.
What is natural selection?
A gradual process by which biological traits become either more or less common in a population.
What is Negative selection?
Reduces reproductive fitness.
- decreases the prevalence of traits.
- leads to gradual reduction of mutant allele
What is positive selection?
Increases reproductive fitness.
- Increases the prevalence of adaptive traits.
- Heterozygote advantage.
What is the effect of small population?
Can exhibit “genetic drift” and cause “founder effect”.
