Estimating Risk of Inherited Disease Flashcards
The frequency of alleles in the whole population affects the health of the population.
population genetics
relative ability of organisms to survive and pass on genes.
“Fitness”
Alleles can affect fitness
Do not affect fitness in most cases
Neutral Allele
Allele that decrease fitness (sometimes)
deleterious allele
Allele that increase fitness (rarely)
advantageous allele
Relative frequencies remain ….
constant
Dominant conditions (alleles) do not become more common at the expense of recessive ones!
Hardy-Weinberg equilibrium (HWE)
Allele frequencies remain constant generation to generation.
Relative proportion of genotype frequencies remain constant generation to generation.
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
Assumptions underlying HWE
Ideal Population
Mutations …… the proportion of new alleles.
increase
Introduction of new alleles as a result of …. or ……….. leads to new gene frequency in hybrid population.
migration
intermarriage
…. increase mutant alleles, thereby increasing proportion of affected homozygotes.
Non-random mating
Choosing of partners due to shared characteristics.
Assortative mating -
Marriage between close blood relatives
Consanguinity
A gradual process by which biological traits become either more or less common in a population
Natural selection
Reduces reproductive fitness. - decreases the prevalence of traits. - leads to gradual reduction of mutant allele.
Negative selection
