| A | B |
|---|
| allele | alternative form for a gene - at identical loci on homologous chromosomes |
| dihybrid cross | genetic cross analyzing the inheritance of two traits simultaneously |
| dominant | allele expressed when only one copy present |
| F1 | first offspring generation in a genetic cross |
| F2 | second offspring generation in a genetic cross |
| gene locus | physical location of a gene on a chromosome |
| genotype | exact genetic makeup of an individual |
| heterozygous | possession of different alleles for a single trait |
| homozygous | possession of only one allele type for a single trait |
| law of independent assortment | segregation of alleles for one trait into gametes not influenced by segregation of alleles of a different trait |
| law of segregation | each organism has two "factors" for each trait, and each gamete contains only one "factor" for each trait |
| monohybrid cross | genetic cross in which the inheritance of only one trait is studied |
| phenotype | physical appearance of an individual |
| Punnett square | a tool for analyzing possible products of genetic crosses - top and side boxes indicate gametes formed in each parent |
| recessive | allele that is expressed only when two copies are present |
| testcross | cross of an offspring to the recessive parental type |
| true-breeding | only produces one type of offspring when self-mated or mated to same genotype |
