Genes accepted as being proven through Dr. Norton's work and their letter designations:

1. Dark - D (D)
2. Marble - M (D)
3. Zebra - Z (D)
4. Gold - g (R)
5. Stripeless - S (D)
6. Smokey - Sm (D)
7. Halfblack - h (R)
8. Gold marble - Gm (D)
9. Pearl - p (R)(note this gene was originally called "pearly." It has become more common to note "pearl" instead.)
10. Streaked - St (D)
11. Veil - V (D)
12. Albino - a (R)

How the genetic notations are applied:

1. The letter designation of a gene name is the first letter in the notation. Sometimes a letter may already be in use such as "G" for Gold. In this case, Gold Marble is given the notation of "Gm." You'll notice the same with the notation "S" which is for stripeless, therefore the genetic notation for Smokey is "Sm" and Streaked is "St." 
2. The first letter can be either uppercase if the gene is dominant to wild-type or lowercase if the gene is recessive. The second letter is always lowercase.
3. Wild-type is designated by (+).
4. a. The preferred written format to separate alleles is with a (/).
ex. for Hybrid Black D/g; for Smokey Sm/+.
b. Fish that are dual-hybrids, tri-hybrids, etc. have loci separated with a (-). ex. for Clown Black Pearl Scale D/+ - Z/S - p/p; for Gold Marble Pearl Scale Gm/g - p/p or Gm/Gm - p/p