| A | B |
|---|
| homozygous | alleles are identical |
| heterozygous | when the genotype includes both a dominant and a recessive allele |
| genotype | symbols used to represent the alleles of an organism |
| phenotype | written description of the trait we observe in an organism |
| dominant | a trait that masks another; represented by a capital letter |
| recessive | a trait that is only expressed in the homozygous form |
| allele | a varying form of a gene |
| Mendel | the father of genetics ( studied pea plants) |
| Punnett square | used to predict probable outcomes of crosses |
| BB x bb | the genotypes of the parents in a typical purebred cross |
| chromosomes | coils of DNA which contain genetic information |
| XX | chromosome genotype for a female |
| XY | chromosome genotype for a male |
| mutation | a change in genes or chromosomes that usually causes death or nonreproduction |
