Estimating Risk of inherited Genetic Disease Flashcards
Define Fitness
The relative ability of an oranism to survive & pass on genes
What do you call a mutant allele that is harmful?
Deleterious
What do you call a helpful mutant allele?
Advantageous
Exaplain population genetics:
The frequencies of certain advantageous & deleterious alleles in a whole population affects the fitness of that population
Determine the frequency of Aa genotype in a 1000 pop. with 190 Aa individuals:
Aa frequency = 190/1000 = 0.19
What does the hardy-weinberg equilibirum (HWE) state about relative genotype frequncies between generations?
The HWE states that between generations relative genotypic frequencies remain constant
Pop. 1000 people.
800AA, 190Aa & 10aa. Whats the frequency of allele A?
1000 people = 2000 alleles
1790A + 210a
frequency of A = 1790/2000 = 0.895
What does HWE state about allele frequencies between generations?
The HWE states that throughout generations allele frequencies will remain even.
If the allele frequency in a generation is: p + q = 1
How do you determine the genotype frequency in the enxt generation?
By squaring p+q=1:
p(squared) + 2pq + q(squared) =1
Therefore if you know the allele frequencies in the first generation you can sub in the values to determine the genotype frequncies in the next generation
What are the characteristics of an ideal population?
- Zero mutation
- Negligible migration
- Random mating
- No selective pressure
- Large size
- =allele frequencies between sexes
Define Assortative mating
Choosing partners due to shared characteristics
Define consanguinity?
Marrying close blood relatives
What two effects occur in a small population?
- Genetic Drift
- The founder effect
Explain genetic drift:
A random fluctutaion in a small pop. where one allele is transmitted to a high proportion of offspring by chance
Explain the founder effect:
A loss of genetic variation when a small subset of a pop. establishes a new colony.
