Population genetics Flashcards
(14 cards)
Gene pool
collection of all alleles in a population
Phenotype frequency
the proportion of different phenotypes
Genotype frequency
the proportion of each genotype
Allele frequency
proportion of alleles in a population
Population definition
a group of individuals from the same species that inhabit similar areas and breeding grounds, that can interbreed to produce fertile offspring
Forces of macroevolution
Natural selection, mutation, genetic drift, migration : all change allele frequency in populations
The Hardy-Weinburg Equilibrium
- model in population genetics for allele and genotype frequency when the 4 forces are not present
Conditions for HWE
no mutations, random mating, no natural selection, large population size, no gene flow
What relationship is the HWE about?
allele (A.F) and genotype (G.F) frequencies
- if the conditions are stable, we can predict
- G.F from A.F
- that A.F wont change from generation to generation
- that G.F wont change after 2nd generation
How is the HWE wrong?
- mutations can never be avoided
- mating is usually non-random
- populations are not completely isolated, migration does occur
- alleles can give survival and reproductive advantage
Genetic drift
random fluctuations in allele frequencies within a population
What does genetic drift explain?
why genetic diversity is higher in larger populations, as it is slower to eliminate alleles, and why there is more genetic diversity than ‘modern synthesis’ predicted
Founder effect
when a small group of individuals establishes a new population that is less genetically diverse
Bottleneck effect
when an event occurs and only a small number of random individuals survive
