genotype - the two genes a person receives for a trait. They are represented by letters.
phenotype - physical trait such as blue eyes, widow's peak, type A blood, etc.
dominant - the gene that is expressed if present. It masks the recessive gene
recessive - the gene that is masked by the dominant. The only way for it to be expressed is for two recessive genes to be present in the genotype
homozygous - both genes in the genotype are the same such as AA or aa
heterozygous - two different alleles in the genotype such as Aa
allele - different forms of a gene. A is the dominant allele while a is the recessive allele.
