Estimating risk of Inherited Disease Flashcards
Define fitness
The relative ability of an organism to survive and pass on genes
What do you call a mutant allele that is harmful?
Deleterious
What do you call a helpful mutant allele?
Advantageous
Explain population genetics
The frequencies of certain advantageous and deleterious alleles in a whole population affects the fitness of that population
Determine the frequency of Aa genotype in a 1000 popular. with 190 Aa individuals
Aa frequency = 190/1000= 0.19
What does the hardy-weinbrug equilbrium (HWE) state about the relative genotype frequencies between generations?
The HWE states that between generations, relative genotypic frequencies remain constant.
Pop 1000 people.
800 AA, 190 Aa and 10aa. Whats the frequency of allele A?
1000 people= 2000 alleles.
(800 * 2) + (190)= 1790 A
(190) + (10 * 2)= 210 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 next 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 frequencies in the next generation
What are the characteristics of an ideal population?
- zero mutation
- negligible migration
- random mating
- no selective pressure
- large sie
- equal allele frequencies between sexes
Define Assortative mating
Choosing partners due to shared characteristics
Define consanguinity
Marrying close blood relatives
What 2 effects occur in a small population?
- genetic drift
- the founder effect
Explain genetic drift
A random fluctuation in a small population 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 population establishes a new colony
