NCEA Level 2 Biology: Genetic Variation & Change Key Definitions

Vocabulary flashcards covering fundamental concepts of genetic variation and population genetics from NCEA Level 2 Biology.

Gene

A section of DNA that codes for a specific protein or trait.

Allele

An alternative form or spelling variation of a gene.

Genotype

The specific pair of alleles inherited for a trait (e.g., $Bb$).

Phenotype

The observable physical characteristics, determined by genotype and environment.

Homologous Chromosomes

Matching maternal and paternal chromosomes with the same genes at the same loci.

Mutation

A permanent change in the base sequence of DNA.

Somatic Mutation

A body cell mutation that affects only the individual and is not inherited.

Gametic Mutation

A sex cell mutation that can be passed on to offspring.

Crossing Over

The exchange of genetic material between non-sister chromatids during meiosis.

Independent Assortment

The random lining up and separation of homologous pairs during meiosis.

Segregation

The separation of alleles into different gametes during meiosis.

Complete Dominance

A pattern where the dominant allele completely masks the recessive allele.

Incomplete Dominance

A pattern where alleles blend to create an intermediate phenotype.

Co-Dominance

A pattern where both alleles are fully and equally expressed together.

Multiple Alleles

When a single gene has more than two possible allele variations in a population.

Lethal Alleles

An allele combination that causes death, changing expected phenotypic ratios.

Linked Genes

Genes located close together on the same chromosome that are inherited together.

Gene Pool

The total collection of all alleles present within a breeding population.

Allele Frequency

A measure of how common a specific allele is within a gene pool.

Natural Selection

Survival and reproduction of individuals with the most favorable phenotypes.

Genetic Drift

Random changes in allele frequencies within a population due to chance events.

Founder Effect

When a small group colonises a new area, creating a low-diversity gene pool.

Bottleneck Effect

A rapid reduction in population size that severely reduces genetic diversity.

Gene Flow

The transfer of alleles into or out of a population via migration.