A genotype is the genetic makeup if an organism. So let's say we have the freckles gene with freckles (F) being dominant and no freckles (f) being recessive. Let's also say Bob is heterozygous so his genotype for the freckles gene would be Ff. If he was homozygous dominant, he would have the genotype FF and if he was homozygous recessive, he would have the genotype ff.