Population Genetics Flashcards
what is population genetics?
understanding the advantages or disadvantages of a change in species
what is phenotypic variation
differences in appearance or function
what is quantitative variation
variation that is measured on a continuum rather than discrete units or categories
doesn’t follow mendelian inheritance patterns
frequently bell shaped distribution
what is qualitative variation
variation that exists in two or more discrete states with intermediate forms often being absent
typically monogenetic
follows mendelian inheritance patterns
what is polymorphism
the existence of discrete variants of character among individuals in a population
what is a recessive allele
will only be expressed if paired with another recessive allele
what is an allele
possesses different versions of the same gene
what is a dominate allele
will be expressed no matter if a recessive one is present
what is evolution
main unifying concept in biology
explaining how the diversity of life in earth arose and how species change over time in response to changes in their abiotic and biotic environment
what is a gene pool
the sum of all alleles at all gene loci in all individuals in a population
what is the hardy- weinberg principle
mathematical model that predicts genotype frequencies: used as a null against which observed data can be compared
used to understand if the changes in the population is or isn’t evolution
used to make predictions of non evolving populations
what are the hardy weinberg principle’s assumptions?
random mating
large population size
no immigration/emigration/ mutation
no selection
what is random mating
everyone has equal chance of mating with everyone in the population
what is large population size
make sure small changes don’t effect the whole population
what is no immigration/emigration/ mutation
closed population and no new genetic variation
what is no selection
no individuals genotype/ phenotype is better than the next
what is genetic equilibrium
the point at which neither the allele frequencies nor the genotype frequencies in a population change in succeeding generations
what happens when random mating
assortative mating
disassortative mating
what is assortative mating
individual of same phenotype mate with each other
increase in homozygous individuals and decrease in heterozygous
what is disassortative mating
each individual mates with the opposite phenotype
increase in heterozygous
what is gene flow
the transfer of genes from one population to another through the movement of individuals or their gametes
what is genetic drift
random fluctuations in allele frequencies as result of chance events; usually reduces genetic variation in a population
what happens when large population size is violated?
small populations, when one change can have big impact on population
small populations have much less genetic diversity making it hard to make predictions
what happens when no migration or emigration is violated
can’t predict what is going to happen to the population
what happens when no selection is violated
only mating with one type of species due to being selected a pon
what is the deleterious alleles
if it is dominate, will be selected against
of recessive, goes un noticed until it shows up in a pair
why are homozygous lethal recessive alleles not removed by selection when a deleterious allele is present
frequency will decrease but carried in heterozygous individuals
what are agents of microevolutionary change
mutation
genetic drift
gene flow
natural selection
non-random mating
what is mutation?
introduction of new genetic variation
genetic variation increases
natural selection
change in frequencies of alleles
non-random mates
may change allelic frequencies
what is directional selection
a type of selection in which individuals near one end of the phenotypic spectrum have the highest relative fitness
what is stabilizing selection
a type of natural selection in which individuals expressing intermediate phenotypes have the highest relative fitness
what is disruptive selection
a type of natural selection in which extreme phenotypes have higher relative fitness than intermediate phenotypes
what is inbreeding
a special form of nonrandom mating in which genetically related individuals mate with each other
what is inbreeding depression
a decline in the average fitness of inbred individuals in a population
what is sexual selection
form of natural selection established by male competition for access to females and by the females’ choice of mates
what is balancing selection
a natural selection in which more than one allele is actively maintained in a population
