| A | B |
|---|
| gene | individual message for a trait; sequence of DNA found on chromosome |
| allele | the different forms of a trait that can be inherited. |
| homozygous | inheriting the same form of the trait from both parents; sometimes called purebred. |
| heterozygous | inheriting different forms of a trait from parent; sometimes called hybrid. |
| chromosome | structure found in the nucleus of cells containing a series of genes. |
| zygote | the diploid cell first formed by the joining of a sperm and egg cell. |
| diploid | cells containing chromosomes in pairs. |
| dominant | the overpowering allele (form of the trait) which prevents the showing of the other form of the trait (alternative allele). |
| recessive | the allele (form of the trait) which is hidden by the dominant allele. |
| incomplete dominance | occurs when neither allele dominates resulting in a blend of the two forms of the trait. |
| haploid cells | cells containing unpaired chromosomes; half the normal number; usually reproductive cells. |
| egg | female haploid cell |
| sperm | male haploid cell |
| genotype | the actual alleles, genetic makeup, of a trait. |
| phenotype | the inherited appearance a trait. |
| sex chromosomes | the pair of chromosomes that determine whether an organism is male or female. |
| sex-linked traits | traits formed by genes found only on the x chromosome. |
| autosomes | the chromosomes which do not determine the sex of the organism. |
| DNA | chemical molecule which creates the genetic codes for traits. |
| cross | the mating of individuals to check for a specific trait. |
