The dominant d-gene is the “dense” gene denoted as “D.”  Dense color gene rabbits can be either “DD” or “Dd.”  We can refer to the “DD” rabbits as “true-breeding” and to the “Dd” rabbits as “carries dilute.”  The “dilute” gene is recessive and is denoted as “d.”  Dilute rabbits are always “dd” and cannot carry the dense gene.  There are just three different combinations of the dense/dilute gene:  “DD,” “Dd,” and “dd.”