The wild-type allele is the most common allele seen for an organism. This is often denoted by ‘+’. Any allele that is not wild-type is shown as ‘­–’. The 2 symbols are separated by a forward slash (/). Therefore, a diploid organism that is homozygous for a wild-type allele at locus R can be shown as +/+. Sometimes the locus abbreviation is given, followed by superscripted wild-type denominators: R^+/+.