| A | B |
| Genetics | the scientific study of heredity |
| True-breeding | the term used to describe organisms that produce offspring identical to themselves if allowed to self-pollinate |
| Trait | a specific characteristic that varies from one individual to another |
| Hybrid | the offspring of crosses between parents with different traits |
| Gene | a sequence of DNA that codes for a protein and thus determines a trait |
| Allele | one of a number of different forms of a gene |
| Segregation | the separation of alleles during gamete formation |
| Gamete | a specialized cell involved in sexual reproduction |
| Probability | the likelihood that a particular event will occur |
| Punnett square | a diagram showing the gene combination that might result from a genetic cross |
| Homozygous | the term used to refer to an organism that has two identical alleles for a particular trait |
| Heterozygous | the term used to refer to an organism that has two different alleles for the same trait |
| Phenotype | the physical characteristcs of an organism |
| Genotype | the genetic make-up of an organism |
| Independent assortment | the independent segregation of genes during the formation of gametes |
| Incomplete dominance | a situation in which one allele is not completely dominant over another |
| Codominance | a situation in which both alleles of a gene contribute to the phenotype of the organism |
| Multiple alleles | three or more alleles of the same gene |
| Polygenic traits | a trait controled by two or more genes |
| Homologous | the term used to refer to chromosomes that each have a corresponding chromosome from the opposite-sex parent |
| Diploid | a term used to refer to a cell that contains both sets of homologous chromosomes |
| Haploid | the term used to refer to a cell that contains only a single set of chromosomes and therefore only a single set of genes |
| Meiosis | a process by which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell |
| Tetrad | a structure containing 4 chromatids that forms during meiosis |
| Crossing-over | the process in which homologous chromosomes exchange portions of their cromatids during meiosis |
| Gene map | a diagram showing the relative locations of each known gene on a particular chromosome |