| A | B |
|---|
| gametes | an organisms reproductive cells such as eggs or sperm |
| gene | a segment of DNA that codes for a protein |
| chromosomes | structures made of DNA that contains the genes, and proteins |
| heredity | the passing of traits from parents to offspring |
| genetics | the study of heredity |
| monohybrid cross | a cross that involves ONE pair of contrasting traits, for example purple flowers or white flowers |
| P generation | the first two individuals that are crossed in a breeding experiment |
| F1 generation | the first generation of offspring from the P generation |
| F2 generation | the offspring of the F1 generation |
| Mendel | father of modern genetics. did experiments with pea plants. |
| 1:1 ratio | half of the offspring have one trait and the other half have the other trait |
| 3:1 ratio | for every 3 individuals with a trait, one individual has the other trait |
| alleles | different versions of a gene, for simplest cases each individual has two of these for every trait |
| dominant | the expressed form of a trait(what you "see"), shown as capital letter, ex. A |
| recessive | the form of the trait that is not expressed(you do not "see" it), shown as lowercase letter, example a |
| homozygous | both alleles are the same, example AA or aa |
| heterozygous | the alleles are different, example Aa |
| genotype | the set of alleles an individual has, like Aa |
| phenotype | the pysical appearance of a trait, like purple flowers |
| Law of Segregation | the two alleles for a trait separate when gametes are formed |
| Law of Independent Assortment | aleles of different genes separate independently of one another during gamete formation |
| dihybrid cross | cross that considers two pairs of contrasting traits |
| Punnett Square | a diagram that can predict the outcomes of genetic crosses by considering all possible combinations |
| test cross | a cross between an individual whose phenotype is dominant, but whose genotype is not known, with a homozygous recessive individual |
| probability | the likelihood a specific event will occur |
| pedigree | a family history that shows how a trait is inherited over several generations |
| sex linked trait | a trait whose allele is on the X chromosome, usually a recessive trait most often expressed in males because they are XY |
| autosome | a chromosome which is not involved in determining gender |
| polygenic trait | many genes are involved, ex. skin color |
| incomplete dominance | blended traits, like red flowers x white giving pink flowers |
| codominance | both forms of a trait are displayed |
| multiple alleles | genes with three or more alleles, ex. blood types A, B, and O. AB also displays codominance. |
| Sickle cell anemia | recessive genetic disorder resulting in defective hemoglobin |
| hemophilia | recessive genetic disorder affecting blood clotting. sex linked. |
| Huntingdon's disease | autosomal dominant disorder that does not appear until victims are older. mental illness, loss of muscle control, and death |
| Cystic fibrosis | recessive. defect in transport protein resulting in mucus clogging many organs especially the lungs |
