Traits are inherited from an organisms parents. Each trait is refered to as a phenotype. Black fur and white fur are phenotypes.

Genes have the directions for producing the various phenotypes. Most genes are paired. Each member of the pair is an allele.One allele is inherited from each parent. Genotype refers to the gene for a particular trait. BB is the genotype for black fur.

Some alleles are dominant and are represented by a capital letter. Recessive alleles are represented by a small letter.

Homozygous refers to having two identical alleles(BB). Heterozygous refers to having different alleles (Bb).