| A | B |
|---|
| true breeding | if an organism has a certain characteristic that is always passed on to all of its offspring |
| allele | one of pair of genes that occupies the same position on homologous chromosomes |
| genotype | two-letter set that represents the alleles an organism possesses for a certain trait |
| phenotype | the observable expression of an organism's genes |
| Homozygous genotype | a genotype in which both alleles are identical |
| heterozygous genotype | a genotype with two different alleles |
| dominant allele | an allele that will determine phenotype if even one is present in the genotype |
| recessive allele | an allele that will not determine the phenotype unless the genotype is homozygous with that allele |
| pedigree | a diagram that follows a particular species' phenotype through several generations |
| monohybrid cross | a cross between two individuals concentrating on only one definable trait |
| dihybrid cross | a cross between two individuals concentrating on two definable traits |
| autosomes | chromosomes that do not determine the sex of an individual |
| sex chromosomes | chromosomes that determine the sex of an individual |
| autosomal inheritance | inheritance of a genetic trait not on a sex chromosome |
| genetic disease carrier | a person who is heterozygous in a recessive genetic disorder |
| sex-linked inheritance | inheritance of a genetic trait located on the sex chromosomes |
| mutation | a radical chemical change in one or more alleles |
| change in chromosome structure | a situation in which abnormal cellular events in meiosis lead to either none of a particular chromosome in the gamete or more than one chromosome in the gamete |
