Population Genetics & Hardy-Weinberg Equilibrium

Vocabulary flashcards covering population genetics, allele and genotype frequencies, Hardy-Weinberg Equilibrium, and evolutionary processes.

Population

A group of individuals of the same species living in the same place at the same time.

Gene Pool

All of the alleles present in a population.

Allele

One version of a gene (for example, $A_1$ or $A_2$).

Genotype

The combination of alleles an individual has (for example, $A_1A_1$, $A_1A_2$, or $A_2A_2$).

Genotype Frequency

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

Allele Frequency

The proportion of all copies of a particular allele in the entire population.

Hardy-Weinberg Principle

The principle stating that reproduction by itself does not change allele or genotype frequencies in a population.

Hardy-Weinberg Equilibrium (HWE)

A state in which allele and genotype frequencies remain constant from generation to generation, indicating that no evolution is occurring at that locus.

Hardy-Weinberg Allele Frequency Equation

$p + q = 1$, where $p$ is the frequency of allele $A_1$ and $q$ is the frequency of allele $A_2$.

Hardy-Weinberg Genotype Frequency Equation

$p^2 + 2pq + q^2 = 1$, where $p^2$ is the frequency of $A_1A_1$, $2pq$ is the frequency of $A_1A_2$, and $q^2$ is the frequency of $A_2A_2$.

Conditions for Hardy-Weinberg Equilibrium

The five required conditions for HWE: 1. No mutation, 2. No natural selection, 3. No gene flow, 4. Very large population (negligible drift), and 5. Random mating.

Mutation

An evolutionary process that creates new alleles, serving as the source of new genetic variation.

Natural Selection

An evolutionary process in which certain heritable traits result in greater reproductive success, causing differential reproduction.

Gene Flow

The movement of alleles between populations as individuals or their gametes migrate.

Genetic Drift

Random changes in allele frequencies across generations, which are especially powerful in small populations.

Nonrandom Mating

Mating patterns (such as sexual selection or mate choice) that change genotype frequencies without necessarily changing allele frequencies.

Evolution

A change in allele frequencies or genetic composition of a population over time across generations.

Modern Synthesis

The integration connecting Darwinian evolution (natural selection) with Mendelian genetics (inheritance) through population genetics.