| A | B |
|---|
| genotype | the alleles of an organism |
| phenotype | the characteristics of an organism |
| dominant allele | an allele that has the same effect on the phenotype whether it is present in the homozygous or heterozygous state |
| recessive allele | an allele that only has an effect on the phenotype when present in the homozygous state |
| codominant alleles | pairs of alleles that both affect the phenotype when present in a heterozygote |
| locus | the particular position on homologous chromosomes of a gene |
| homozygous | having two identical alleles of a gene |
| heterozygous | having two different alleles of a gene |
| carrier | an individual that has one copy of a recessive allele that causes a genetic disease in individuals that are homozygous for this allele |
| test cross | testing a suspected heterozygote by crossing it with a known homozygous recessive |
| sex linkage | the condition in which a gene responsible for a specific trait is located on a sex chromosome, resulting in sexually dependent inheritance of the trait |
