Estimated risk inherited disease

Question 1

Discuss the clinical relevance of population selection pressures and ethnic genetic variation.
-Fitness and how it is affected

Answer 1

Fitness: the Ability of an organism to reproduce and pass on its alleles( neutral, deleterious, advantageous)
The frequency of alleles in a population defines their fitness.
In an ideal population the frequency of alleles remains constant from one population to the next.
However:
-Migration and mutation: movement of population introduces new alleles
-Random breeding: consanguinity/ tendency to be attracted to individuals with shared characteristics
-Natural selection:
positive: increases reproductive fitness, increases heterozygotes, increases adaptive traits
negative: decreases reproductive fitness , prevalence of traits, mutant alleles
-Large population: Genetic bottlenecks-increase in frequency of one allele by chance
founder effect-new colony created from small group
Bottleneck effect- brought on by a natural disaster.
e.g. of founder effect:
-Dominant: BRCA1 trait in polish, scandinavian, lithuanian.
-Recessive: CF in wester europeans

HWE used for:

• screening tests
• calculating risks in genetic councellimg