CB1.3 Genetic Variation Comprehensive NCEA Level 1 Study Guide (copy)

Genetic Variation

The structural, physiological, or functional differences present between individuals of the same species.

Continuous Variation

Variation displaying a continuous range of quantitative values without distinct categories, controlled by multiple genes and environmental factors.

Discontinuous Variation

Variation displaying distinct, non-overlapping categories with no intermediate values, such as blood groups.

Inheritable Variation

Variations encoded in the base sequence of DNA that can be passed to offspring.

Non-Inheritable Variation

Variations acquired during an individual's lifetime due to environmental factors, not passed to offspring.

Phenotype

An organism's observable characteristics determined by the genotype and environmental factors.

Mutation

A permanent, random change in the base sequence of DNA; the ultimate source of new genetic variation.

Somatic Mutations

Mutations occurring in body cells that cannot be passed to offspring.

Gametic Mutations

Mutations occurring in sex cells that can be passed to future generations.

Natural Selection

The process where individuals with advantageous traits survive and reproduce at higher rates, leading to adaptations in populations.

Peppered Moth Selection

An example of natural selection where dark morphs gained advantages by camouflaging in polluted environments.

Population Bottleneck

A drastic reduction in population size due to catastrophic events, leading to decreased genetic variation.

Gene Flow

Migration of individuals into or out of a population, introducing or removing alleles.

Karyotype

A visual representation of the complete set of chromosomes in a cell, useful for evaluating genetic abnormalities.

Purebred

An individual homozygous for a specific trait, producing identical offspring when bred with another purebred.

Test Cross

A genetic test to determine whether a dominant phenotype individual is homozygous or heterozygous.

Down Syndrome

A genetic disorder caused by an extra copy of chromosome 21 (Trisomy 21).

Cancer

A condition arising from unrepaired DNA mutations, leading to uncontrolled cell growth.

Lactose Persistence

A genetic adaptation resulting from a mutation allowing some adults to digest lactose.

DNA Polymerase

An enzyme that joins nucleotides to synthesize DNA strands during replication.

Allele

An alternate form or version of a specific gene.

Gene

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

Chromosome

A long, coiled length of DNA that contains many genes.