Population Genetics Concepts

Flashcards covering population genetics, Hardy-Weinberg equilibrium, natural selection, and genetic drift.

Hardy-Weinberg Equilibrium

Describes a population that is not evolving, where allele and genotype frequencies remain constant over generations.

Hardy-Weinberg Equation Conditions

No new mutations, no genetic drift, no migration, no natural selection, and random mating.

Inbreeding

Mating between genetically related individuals; disrupts HW equilibrium by favoring homozygotes.

p

Represents the frequency of the dominant allele in the Hardy-Weinberg equation.

q

Represents the frequency of the recessive allele in the Hardy-Weinberg equation.

p²

Represents the frequency of the homozygous dominant genotype.

2pq

Represents the frequency of the heterozygous genotype.

q²

Represents the frequency of the homozygous recessive genotype.

Directional Selection

Favors one extreme phenotype, leading to a shift in the population's traits.

Disruptive Selection

Creates two or more contrasting phenotypes, often in heterogeneous environments.

Balancing Selection

Maintains genetic diversity in a population by favoring heterozygous individuals.

Stabilizing Selection

Favors the survival of individuals with intermediate phenotypes, decreasing genetic diversity.

Genetic Drift

Random changes in allele frequencies due to chance fluctuations in a population.

Bottleneck Effect

A significant reduction in population size that leads to a loss of genetic diversity.

Founder Effect

Occurs when a small group establishes a new population, leading to reduced genetic diversity.

Random Mating

Individuals choose their mates regardless of their genotypes and phenotypes; a condition for HW equilibrium.

Assortative Mating

Individuals do not mate randomly.

Positive Assortative Mating

Individuals are more likely to mate due to similar phenotypic characteristics.

Negative Assortative Mating

Individuals with dissimilar phenotypes mate preferentially, increasing heterozygosity.