2.1.9 - Punnet Squares

Punnett Square

A table that predicts the genotypes of a particular genetic cross and determines the probability of genotypes and phenotypes in offspring.

Monohybrid Cross

A cross between two individuals differing in one trait that is controlled by only one gene.

True Breeding

Individuals that when crossed together produce offspring with the same genotype and phenotype as the parents for the trait.

Hybrid

Offspring produced by crossing two true-breeding individuals with different traits, expressing the dominant trait phenotypically.

Test Cross

A cross between an individual with the dominant phenotype and an individual with the recessive phenotype to determine the genotype of the dominant individual.

Phenotype Ratio

The ratio of different phenotypes that result from a genetic cross, determined by the genotype ratio.

Genotype Ratio

The ratio of different genotypes that result from a genetic cross.

Heterozygous

An organism with two different alleles for a specific trait.

Homozygous

An organism with two identical alleles for a specific trait.

Allele

One of two or more forms of a gene found at the same place on a chromosome.