| A | B |
|---|
| genetics | the scientific study of heredity |
| trait | a characteristic that can be passed from parent to offspring |
| purebred | any organism that receives the same genetic information from each of its parent |
| hybrid | an organism that receives different forms of a genetic trait from each parent |
| genes | sections of a chromosome that code for a trait |
| allele | a distinct form of a gene |
| dominant allele | a form of a gene that is fully expressed when two different alleles are present |
| recessive allele | a form of a gene that is not expressed when paired with a dominant allele |
| chromosome theory of heredity | Walter Sutton's idea that states that the material of inheritance is carried by the genes in chromosomes |
| genotype | the genetic makeup of an organism |
| phenotype | the physical appearance of the trait |
| homozygous | an organism in which the two alleles in a gene pair are identical for that trait |
| heterozygous | an organism in which the two alleles for a particular trait are different |
| Punnett square | a grid for organizing genetic informaion |
| test cross | the cross of homozygous recessive and an unknown genotype resulting in offspring with observable phenotypes |
| pedigree | a chart that shows how a trait and the genes that control it are inherited within a family |
| carrier | an individual who carries a recessive trait that is not expressed |
| incomplete dominance | a pattern of inheritance in which two alleles in a heterozygote are partially expressed |
| codominance | a pattern of inheritance in which both alleles in a heterozygote are fully expressed |
| polygenic trait | a trait controlled by two or more gene pairs |
| multiple alleles | the presence of more than two alleles for a gene in a population |
| pleiotropy | a single gene that affects more than one trait |
| sex-linked trait | this type of trait shows up more often in males, gene is on X chromosome |
| XY | male sex chromosomes |
| XX | female sex chromosomes |
| albinism | genetic disorder where no melanin is produced |
| huntington disease | dominant disorder that destroys nervous system |
| cystic fibrosis | recessive disorder that affects lungs and digestive system |
| Tay-Sachs | recessive disorder that causes buildup of lipids in brain, causes death at an early age |
| sickle cell anemia | recessive disorder found mainly in African-Americans, causes misshapen hemoglobin |
| Blood Type A | can either be AA or Ao |
| Blood Type B | can either be BB or Bo |
| Blood Type AB | has genes AB |
| Blood type O | has genes oo |
| Mendel | Father of Genetics, bred pea plants and developed Laws of Heredity |
| P generation | parental generation, Mendel crossed purebred plants for contrasting traits |
| F1 generation | first filial generation, Mendel allowed hybrid plants to self pollinate |
| F2 generation | second filial generation, here Mendel saw 3 dominant to every one recessive phenotype |
| Law of Segregation | explains that alleles for a single trait separate during meiosis |
| Law of Independent Assortment | this explains that alleles for different traits are divided randomly during meiosis |
