Allele – either of the two paired genes which affect an inheritable trait.

Co-dominant – a gene that causes the homozygous form to look different than the wild-type and the heterozygous form to have traits of both.

DNA (Deoxyribonucleic Acid) – molecules bearing genetic information of all living cells. Gene. Also referred to as “unit of inheritance.”

Dominant – a gene that causes an animal to look different than the wild-type and where the homozygous form and the heterozygous form look the same as each other.

Double Heterozygous – being heterozygous for two different traits.

Gene – unit of heredity that determines the characteristics of the offspring.

Genetics – the study of heredity.

Genotype – an organism’s genetic composition. Heredity – the transmission of genetic characters from parents to offspring.

Het – an abbreviation for heterozygous.

Heterozygous – possessing two different genes for a given trait. An animal with one mutated, recessive gene still appears normal; its mutated gene can be inherited by future offspring. A codominant animal is heterozygous for the dominant form of its mutated gene, yet is different in appearance than both the wild-type and homozygous forms.

Homozygous – A state in which both genes for a specific trait are the same. When a recessive gene is it its homozygous form, it makes the animal look different from the wild-type. When a dominant gene is in its homozygous state, it causes the animal to look different from both the wild-type and the heterozygous (codominant) forms.

Locus – a gene’s position on a chromosome (plural: loci)

Mutation – an abnormal gene that under certain circumstances can cause an animal to be born with an appearance other than wild-type.

Normal – an animal with no mutated genes – “wild type” in appearance. (See wild type)

Phenotype – an animal’s external apperance, as caused by its genotype.

Possible Het. – an animal from a known breeding that has either a 50% or 66% possibility of being “heterozygous” for a mutant gene.

A 66% possible het comes from breeding 2 heterozygous animals together: 50% of the offspring are heterozygous, 25% will be homozygous, and 25% will be wild-type. Of the normal appearing animals, 66% (or roughly 2 out of 3) will actually be heterozygous for the mutated gene.

A 50% possible het comes from breeding a heterozygous animal to a wild-type animal. All of the resulting offspring will be wild-type in appearance, but 50% of them will actually be heterozygous for the mutated gene and must be bred out to determine which animals are really hets.

Recessive – a gene that affects an animal’s appearance if it’s present in the homozygous state. A heterozygous animal carrying a mutated, recessive gene looks normal.

Super – commonly used herpetocultural term for the dominant form of a co-dominant mutation. i.e. Super Pastel

Tyrosinase – an enzyme required for synthesizing melanin.

Tyrosinase-negative – an albino whose cells lack tyrosinase, producing a white and yellow/orange animal with pink eyes. A separate albino mutation from tyrosinase-positive. Also called T- .

Tyrosinase-positive – an albino not able to synthesize melanin, but capable of synthesizing tyrosinase, which results in lavender-brown skin color. Also referred to as T+ .


Examples of Recessive Traits:


Lavender Albino


Black Axanthic

Caramel Albino


Genetic Stripe

Ghost (Hypo)

Orange Ghost

Desert Ghost

Piebald (Pied)


Examples of Co-Dominant Traits and its Super Form:

Butter / Blue Eyed Leucistic

Lesser / Blue Eyed Leucistic

Mojave / Super Mojave

Mystic / Super Mystic

Enchi / Super Enchi

Fire / Black Eyed Leucistic

Pastel / Super Pastel

Yellowbelly / Ivory

Cinnamon / Super Cinnamon

Black Pastel / Super Black Pastel

GHI / Super GHI

Scaleless Head / Scaleless


Examples of Dominant Traits:





Breeding Scenarios:

Co-Dominant x Normal

Pastel x Normal = ½ Pastels, and ½ Normals


Co-Dominant (Super Form) x Normal

Super Pastel x Normal = All Pastel


Co-Dominant x Co-Dominant

Pastel x Pastel = ½ Pastels, ¼ Super Pastels, and ¼ Normals


Dominant x Normal

Pinstripe x Normal = ½ Pinstripes, and ½ Normals


Dominant x Dominant

Pinstripe x Pinstripe = All Pinstripes


Recessive x Normal

Albino x Normal = All Het. Albinos


Recessive x Het. Recessive

Albino x Het. Albino = ½ Albinos, and ½ Het. Albinos


Recessive x Recessive

Albino x Albino = All Albinos


Het. Recessive x Het. Recessive

Het. Albino x Het. Albino = ½ Het. Albinos, ¼ Albinos, and ¼ Normals


Co-Dominant x Recessive

Pastel x Albino = ½ Pastels Het. Albinos, and ½ Het. Albinos