Trait
Characteristic that is inherited; can be either dominant or recessive.
P Generation
Stands for parental generation. The true-breeding parent individuals who make the F1 hybrid offspring.
F1 generation
The first filial, hybrid (heterozygous) offspring arising from a P generation cross.
F2 generation
The offspring resulting from interbreeding (or self-pollination) of the hybrid F1 generation.
Allele
Different forms of a trait
Dominant allele
The allele that is more powerful. Will always see this version if a gene as long as one allele is this.
Recessive Allele
The allele that can be covered up by a dominant form. We will only see this version of a gene if we have 2 of these alleles.
Genotype
The genetic makeup, or set of alleles, of an organism. (Ex: PP, Pp or pp) (Type of gene)
Phenotype
The physical traits of an organism, which are determined by its genes.
Punnett Square
A diagram used to show the predicted genotypic and phenotypic results of a genetic cross between individuals of known genotype.
Homozygous
Having two identical alleles for a given gene; RR or rr.
Heterozygous
Having two different alleles for a given gene. Rr
Dihybrid Cross
A cross between two organisms looking at two different traits.
Incomplete Dominance
The situation in which the phenotype of heterozygotes is a blended mix between the phenotypes of individuals homozygous for either allele.
Codominance
The situation in which the phenotypes of both alleles show up in the heterozygote because both alleles affect the phenotype in separate, distinguishable ways.
Multiple Alleles
Three or more forms of a gene that code for a single trait (still only have two alleles per gene). Classic example is blood type.
Sex Chromosomes
The 23rd pair of chromosomes in humans that determine the sex (or gender) of the individual. Women are XX and Men are XY.
Polygenic
Traits that are controlled by more than one gene, ex: skin color and hair color.
Pedigree
A genetic tool that looks at the history of a genetic disorder in a family.
Hybrid
Another word for heterozygous -- Bb
Purebred
Another word for homozygous -- BB
genetics
Scientific study of heredity
Gregor Mendel
Father of Genetics! Augustinian monk and botanist whose experiments in breeding garden peas led to his eventual recognition as founder of the science of genetics (1822-1884)