Biology 1620 Introduction to Evolution

Allele Frequency

The proportion of a specific allele (version of a gene) among all allele copies at a certain locus in a population.

Hardy-Weinberg Equilibrium

A null model stating that allele and genotype frequencies in a population will remain constant in the absence of evolutionary forces.

Genetic Drift

A change in allele frequencies due to random chance. It has a much larger effect in small populations.

Gene Flow

The transfer of genetic material between populations via migration, which tends to homogenize populations.

Bottleneck Effect

A sharp reduction in population size due to an environmental event, resulting in a loss of genetic diversity.

Founder Effect

When a small group breaks off from a larger population to establish a new colony, carrying only a fraction of the original genetic variation.

Allele

An alternative version of a gene that resides at a specific locus on a chromosome.

Allele Inheritance

In diploid organisms, individuals inherit one allele from each parent for every gene.

Homozygous Genotype

Having two identical alleles at a locus (AA or aa).

Heterozygous Genotype

Having two different alleles at a locus (Aa)

Dominant Allele

An allele that masks the effect of a recessive allele.

Recessive Allele

An allele expressed only when the individual is homozygous (aa) for that trait.

Genotype

classification system categorizing organisms by genetic traits; including full hereditary info or part of genomic sequences, they are one of the three factors that determine phenotype.

Phenotype

composite of the organism's observable characteristics or traits resulting from the interaction of its genotype with the environment.