(1) Monohybrids and the Punnett Square Guinea Pigs

Allele

A form of a gene, often represented by a letter.

Dominant Allele

An allele that shows its effect even when only one copy is present; represented by a capital letter.

Recessive Allele

An allele that only shows its effect when two copies are present; usually represented by a lowercase letter.

Genotype

The genetic makeup of an organism, represented by letters (e.g., HH, Hh, hh).

Phenotype

The physical traits of an organism, determined by its genotype.

Homozygous

Having two identical alleles for a particular gene (e.g., HH or hh).

Heterozygous

Having two different alleles for a particular gene (e.g., Hh).

Monohybrid Cross

A genetic cross that involves one trait; represented using a Punnett square.

Punnett Square

A diagram used to predict the genotypes and phenotypes of offspring from a genetic cross.

Phenotype Ratio

The ratio of different physical traits in the offspring (e.g., 3 with hair: 1 hairless).

Genotype Ratio

The ratio of different genetic makeups in the offspring (e.g., 1 HH: 2 Hh: 1 hh).