Allele Frequencies In Populations Flashcards
What is an allele?
An allele is a variant form of a gene.
Define allele frequency.
Allele frequency is the proportion of a specific allele among all allele copies in a population.
True or False: Allele frequencies can change over time.
True.
What is the Hardy-Weinberg principle?
The Hardy-Weinberg principle states that allele frequencies in a population will remain constant from generation to generation in the absence of evolutionary influences.
Fill in the blank: The equation for the Hardy-Weinberg principle is ___ + 2pq + q^2 = 1.
p^2
What do the variables p and q represent in the Hardy-Weinberg equation?
p represents the frequency of the dominant allele, and q represents the frequency of the recessive allele.
True or False: A population in Hardy-Weinberg equilibrium is evolving.
False.
List one condition necessary for Hardy-Weinberg equilibrium.
A large population size.
What is genetic drift?
Genetic drift is the change in allele frequencies due to random sampling effects, particularly in small populations.
What is the effect of natural selection on allele frequencies?
Natural selection can increase the frequency of beneficial alleles and decrease the frequency of harmful alleles.
Fill in the blank: Mutation introduces new ___ into a population.
alleles
What is gene flow?
Gene flow is the transfer of genetic material between populations through migration.
True or False: Gene flow can increase genetic diversity within a population.
True.
What is a bottleneck effect?
The bottleneck effect is a sharp reduction in the size of a population due to environmental events, leading to reduced genetic diversity.
What is founder effect?
Founder effect occurs when a small group from a population establishes a new population, resulting in a limited gene pool.
What is the significance of allele frequencies in population genetics?
Allele frequencies are used to understand genetic variation, evolution, and population structure.
True or False: Allele frequencies are the same in all populations.
False.
What does it mean if an allele is said to be fixed in a population?
An allele is fixed in a population when its frequency is 100%.
Fill in the blank: The Hardy-Weinberg equilibrium is maintained under the assumption of ___ mating.
random
What is the role of sexual reproduction in allele frequencies?
Sexual reproduction shuffles alleles, promoting genetic variation and influencing allele frequencies.
What is an example of a factor that can disrupt Hardy-Weinberg equilibrium?
Natural selection.
True or False: In a population undergoing genetic drift, allele frequencies can fluctuate significantly over time.
True.
What type of selection favors extreme phenotypes?
Directional selection.
Fill in the blank: In stabilizing selection, the intermediate phenotype has a ___ fitness.
higher
What is disruptive selection?
Disruptive selection favors individuals at both extremes of the phenotypic range.
What does the term ‘genetic variation’ refer to?
Genetic variation refers to the diversity of alleles and genotypes within a population.
What is the impact of inbreeding on allele frequencies?
Inbreeding can increase the frequency of harmful recessive alleles and reduce genetic diversity.
True or False: Environmental changes can lead to shifts in allele frequencies.
True.
What is the purpose of calculating allele frequencies in conservation biology?
To assess genetic diversity and inform breeding programs for endangered species.
Fill in the blank: The measure of genetic diversity in a population is called ___ diversity.
allelic
What is the impact of habitat fragmentation on allele frequencies?
Habitat fragmentation can reduce gene flow and increase genetic drift, leading to changes in allele frequencies.
What is an example of a mutation that can affect allele frequency?
A point mutation that confers resistance to a disease.
True or False: All mutations are beneficial.
False.
What is the relationship between population size and genetic drift?
Genetic drift has a more pronounced effect in smaller populations.
Fill in the blank: The frequency of an allele is calculated as the number of copies of that allele divided by the total number of ___ for that gene.
alleles
What is the significance of studying allele frequencies in human populations?
To understand human genetic diversity, disease susceptibility, and evolutionary history.
What is the term for the genetic makeup of an individual?
Genotype.
True or False: Phenotype is influenced solely by genotype.
False.
What is the definition of a polymorphism?
A polymorphism is the occurrence of two or more distinct alleles at a locus in a population.
Fill in the blank: The study of allele frequencies is a key component of ___ genetics.
population
What is the effect of selective pressure on allele frequencies?
Selective pressure can lead to an increase in the frequency of advantageous alleles.
What is a quantitative trait?
A quantitative trait is a trait that is influenced by multiple genes and can be measured on a continuous scale.
True or False: All traits are controlled by a single gene.
False.
What is the relationship between allele frequency and evolutionary change?
Changes in allele frequency over time indicate evolutionary change within a population.
Fill in the blank: The process by which one species evolves into two or more species is called ___ speciation.
adaptive
What is the role of recombination in allele frequency?
Recombination creates new allele combinations, contributing to genetic diversity and potentially affecting allele frequencies.
What is the significance of studying allele frequencies in agriculture?
To select for desirable traits and improve crop and livestock breeds.
True or False: Allele frequencies are static and do not change.
False.
What is the main factor that maintains genetic diversity in a population?
Gene flow.
Fill in the blank: A population with low genetic diversity is more susceptible to ___ pressures.
environmental
What does it mean if an allele is considered to be at a frequency of 0?
It means that the allele is not present in the population.
What is the relationship between allele frequency and fitness?
Allele frequency can be influenced by the fitness of the alleles, with higher fitness alleles becoming more common.
True or False: Genetic variation is essential for a population’s ability to adapt to changing environments.
True.
What is the primary method for measuring allele frequencies?
Genetic analysis through DNA sequencing or genotyping.
Fill in the blank: The study of allele frequencies helps in understanding ___ evolution.
micro
What is the potential impact of climate change on allele frequencies?
Climate change can alter selective pressures, leading to shifts in allele frequencies as populations adapt.
What is the definition of a fixed allele?
A fixed allele is one that is the only variant present in a population at a specific locus.
True or False: The founder effect can lead to reduced genetic variation.
True.
What is the result of positive selection on allele frequencies?
Positive selection increases the frequency of advantageous alleles.
Fill in the blank: A population undergoing ___ selection will have a decrease in allele diversity.
directional
What is the effect of negative selection on deleterious alleles?
Negative selection tends to decrease the frequency of deleterious alleles.
What is the significance of allele frequency data in medicine?
It helps identify genetic predispositions to diseases and informs public health strategies.
True or False: Genetic tools can help track changes in allele frequencies over time.
True.
What is the role of environmental factors in shaping allele frequencies?
Environmental factors can create selective pressures that influence which alleles are favored in a population.
Fill in the blank: The study of allele frequencies contributes to our understanding of ___ diversity.
biodiversity
What is the relationship between allele frequency and population structure?
Population structure can influence allele frequencies due to varying levels of gene flow and genetic drift.
True or False: Allele frequencies can be influenced by human activity.
True.
What is the purpose of conservation genetics?
To maintain and restore genetic diversity in endangered species populations.
Fill in the blank: Genetic diversity is essential for a population’s ___ to survive environmental changes.
ability
What is a locus?
A locus is the specific physical location of a gene or allele on a chromosome.
