| A | B |
|---|
| true breeding | has a homozygous genotype |
| hybrid | has a heterozygous genotype |
| monohybrid cross | a cross involving only one trait |
| P generation | the original parental generation that is crossed |
| F1 generation | the children of the P generation |
| F2 generation | the children of the F1 generation |
| alleles | different forms of a gene such as P for purple and p for yellow are different alleles |
| dominant | the gene that is expressed if present. It will mask the appearance of the recessive gene |
| recessive | the gene that is masked by the dominant. It will only appear when the dominant gene is not present |
| homozygous | both genes in the genotype are the same |
| heterozygous | two genes in the genotype are different |
| genotype | the genes one receives for traits - represented by letters |
| phenotype | physical trait or appearance |
| dihybrid cross | a cross involving two traits on separate chromosomes |
| trihybrid cross | a cross involving 3 traits on separate chromosomes |
| incomplete dominance | neither gene is truly dominant. A hterozygous genotype gives you a blend between the two |
| codominance | both genes are equally expressed |
| multiple alleles | there are more than 2 alleles for the trait such as we see with ABO blood type |
| sex-linked traits | traits found on either the X or Y chromosome |
| sex influenced traits | traits that are NOT found on the sex chromosomes but on the autosomes. However, the way that they are expressed is influenced by one's sex. An example is baldness. |
| epistasis | the expression of genes is determined by other control genes that either permit or prevent these genes from being expressed |
| linked genes | the genes for two traits are on the same chromosome |
| polygenic traits | traits in which the degree of expression is controlled by different combinations of genes (example: skin pigmentation) |
