| A | B |
| heredity | the passing of traits from parents to offspring |
| genetics | the study of inheritance |
| genes | pieces of genetic material that determine traits |
| dominant allele | the strong form of a gene, expressed even if a weaker gene is present |
| recessive allele | the weak form of a gene, not expressed when the dominant form is also present |
| phenotype | a trait that an organism actually shows |
| genotype | gene combination that determines phenotype |
| hybrid | a genotype which is a combination of two different alleles for the same gene (one dominant, one recessive) |
| gametes | sex cells that unite to form a zygote |
| incomplete dominance | a condition that results when genes produce a trait somewhere in between the traits of parents |
| meiosis | nuclear division that produces gametes or spores having one set of unpaired chromosomes |
| X chromosome | the longer sex chromosome (females have two, males have one) |
| Y chromosome | the shorter sex chromosome, found in males |
| mutation | a change in DNA or chromosomes; can occur in body cells or sex cells; often causing death of cell |
| replication | copying process in which new DNA is created |
| Gregor Mendel | the Father of Genetics |
| heterozygous | having two different alleles for a trait |
| homozygous | having two of the same alleles for a trait |