population genetics Flashcards
gene pool
all the alleles of every gene in a population
what do population geneticist study?
genetic variation within the gene pool and how it changes form one generation to the next
monomorphic
gene that predominantly has only one allele
polymorphic
gene with 2 or ore alleles, or non-coding piece of DNA that shows variation in sequence
what does evolution cause?
allele and genotype frequencies changing over the course of generations
Hardy-Weinberg Equation is used for?
to define a relationship between allele or gene frequencies/ to determine if a population is evolving
different allele frequencies are seen in
populations
conditions that needs to be met to be able to use the Hardy-Weinberg Equation
no selection, no mutation, no migration, large population, random mating
What is the Hardy-Weinberg Equation
(p^2)+2pq+(q^2)=1
what does microevolution do
changes a population’s gene pool from generation to generation
what does microevolution do
changes in a population’s gene pool from generation to generation
what is microevolution driven by?
mutation, natural selection, genetic drift, migration, nonrandom mating
directional selection
favors survival of one extreme phenotype which is better adapted to an environmental condition
balancing selection
favors maintenance of 2 or more alleles, population isn’t evolving toward either allele
disruptive selection
favors survival of 2 or more genotypes with DIFFERENT phenotypes, caused by fitness for a genotype to vary in different environments
stabilizing selection
favors survival of individuals with intermediate phenotypes, extreme phenotypes selected against
decreases diversity of alleles for a particular gene
stabilizing selection
genetic drift
random changes in allele frequencies due to chance
founder effect
migration of only a few individuals to establish a new local population
bottleneck effect
dramatic reduction in population size, population is re-establish by only a few individuals
gene flow
individuals migrate between populations with different allele frequencies
conglomerate
population that gains the migrants
non-random mating
individuals do not pick mates randomly, they pick mates based on phenotype
population
a group of individuals of the same species that occupy the same region and can breed with each other
how is directional selection initiated
due to a new allele in a population and change in environment
how does migration change allelic frequencies
bringing in more copies of an allele already in the population or by bringing in a new allele that has arisen by mutation
