Genotype, Allele Frequencies, and Evolution

A comprehensive set of 60 vocabulary flashcards covering essential concepts on genotype, allele frequencies, and principles of evolution.

Genotype

The genetic constitution of an individual.

Allele Frequency

The proportion of a specific allele in a population.

p

Frequency of allele A.

q

Frequency of allele a.

p + q = 1

The sum of the frequencies of all alleles in a population must equal one.

f(AA)

Frequency of the homozygous dominant genotype.

f(Aa)

Frequency of the heterozygous genotype.

f(aa)

Frequency of the homozygous recessive genotype.

p²

The expected frequency of genotype AA.

2pq

The expected frequency of genotype Aa.

q²

The expected frequency of genotype aa.

Hardy-Weinberg Equilibrium

A state where allele and genotype frequencies remain constant in a population.

No Mutation

One of the conditions for Hardy-Weinberg equilibrium requiring no changes in allele structure.

Random Mating

Mating that occurs without regard for genotype or phenotype.

No Natural Selection

A condition where all individuals have equal reproductive success.

Large Population Size

A condition minimizing genetic drift effects.

No Migration

Absence of gene flow between populations.

Allele Frequencies Constant

Key prediction of the Hardy-Weinberg model.

Genotype Frequencies Proportional

The expected ratios of p² : 2pq : q² under Hardy-Weinberg equilibrium.

Phenotype Frequency

The proportion of individuals displaying a particular trait.

Chi Square Test (χ² test)

Statistical test to compare observed and expected frequencies.

Degrees of Freedom (df)

The number of genotypes minus the number of alleles.

Microevolution

Small-scale evolutionary changes within a population.

Macroevolution

Large-scale evolutionary changes above the species level.

Mutation

A heritable change in the DNA sequence.

Natural Selection

Differential reproduction based on heritable variation.

Fitness

The relative reproductive success of a genotype.

Diversification of Alleles

The process by which new alleles are introduced into a population.

Founder Effect

Reduced genetic diversity resulting from a small group forming a new population.

Bottleneck Effect

A decrease in genetic diversity due to a significant reduction in population size.

Genetic Drift

Random changes in allele frequency due to small population sizes.

Endogamy

Mating within a specific group.

Admixture

The mixing of two genetically distinct populations.

Cline

A gradual change of allele frequency across geographic space.

Positive Selection

Favors beneficial alleles and increases their frequency.

Negative Selection

Removes harmful alleles and decreases their frequency.

Balanced Polymorphism

Maintained genetic variation due to heterozygote advantage.

Genetic Load

The burden of deleterious mutations in a population.

Directional Selection

Favors one extreme phenotype, shifting trait mean.

Stabilizing Selection

Favors intermediate phenotypes, reducing variation.

Disruptive Selection

Favors both extremes of phenotypes, which can lead to speciation.

Eugenics

Intentional manipulation of human reproduction to 'improve' traits.

Gene Flow

Movement of alleles between populations.

Genetic Equilibrium

State where allele frequencies do not change over generations.

Allele Pool

The complete set of alleles in a population.

Homozygous

Having identical alleles for a particular gene.

Heterozygous

Having different alleles for a particular gene.

Recessive Allele

An allele that is masked when a dominant allele is present.

Dominant Allele

An allele that expresses its trait even in the presence of a recessive allele.

Speciation

The formation of new and distinct species in the course of evolution.

Extinction

The end of an organism or a species.

Genotype Frequency Proportion

The proportion of individuals with a specific genotype in a population.

Allelic Variation

Differences in alleles within a population.

Genetic Diversity

The total number of genetic characteristics in the genetic makeup of a species.

Reproductive Success

The passing of genes to the next generation in a way that they too can pass on those genes.

Adaptation

The process by which a species becomes better suited to its environment.

Key Assumptions of Hardy-Weinberg

No mutation, random mating, no natural selection, large population, no migration.

Genotype Frequencies Must Sum to 1

The total frequency of all possible genotypes in a population equals one.