Terms used within the community

Amelanism (Amel)

A pigmentation abnormality characterized by the lack of pigment called melanin, commonly associated with a genetic loss of tyrosinase function which produces dark brown/black pigment, often leading to very pale individuals which may still have other colours present.

 Melanism

An overabundance of melanin, producing black animals.

 Albinism

A hereditary condition characterised in animals by the absence of pigment in the eyes, skin, hair, scales, feathers or cuticle. This results in an all white animal, usually with pink or red eyes.

 Hypomelanism (Hypo)

A reduction but not complete lack of dark pigment (melanin.) Animals usually have black eyes.

 Hypermelanistic

An animal with an increased amount of melanin in the skin, giving it a colour that is significantly darker than normal but not necessarily completely black.

 Flavistic

A colour mutant that has a yellow or golden colour.

 Anerythristic

Lacking red pigment.

 Axanthic

Lacking yellow pigment.

 Xanthic

Having more yellow pigment than normal.

 Erythristic

Having a greater amount of red coloration than usual.

 Leucistic

Developmental mutation where pigment cells do not migrate from neural crest expressing animals that are usually white with more or less dark spots / patches and black eyes.

Ivory

Usually a term used with Sulcata Tortoises. Refers to Leucism. (directly above)

Morph

Refers to a genetic mutation outside of the “wild type” characteristics. IE any of the above.

Chromatophores

Pigment-containing and light-reflecting cells. Subcategorised as below:

Xanthophores

Yellow pigment.

Erythrophores

Red pigment.

Leucophores

White pigment.

Melanophores

Black/brown pigment.

Cyanophores

Blue pigment.

 Tyrosinase

An oxidase that is the rate-limiting enzyme for controlling the production of melanin.

T- albino

Lacks melanin because it cannot make functional tyrosinase. Generally has red eyes.

T+ albino

Lacks melanin in spite of being able to make functional tyrosinase. Generally has black eyes.

 Homozygous

The two genes in the gene pair are the same.
Heterozygous (Het)

The two genes in the gene pair are NOT the same.

A heterozygous animal has a heterozygous gene pair.
A heterozygous gene pair is made up of:

 A dominant mutant gene and a normal gene.

A co-dominant mutant gene and a normal gene.

A recessive mutant gene and a normal gene.

Two different mutant genes.

 So a heterozygous animal does not have to look normal. Ie, like the wild type.

A double het has two heterozygous gene pairs.

Allele

Each of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.

 Dominant allele

An allele that produces the same phenotype whether its paired allele is identical or different.

 Recessive allele

An allele that produces its characteristic phenotype only when its paired allele is identical.

 Co-dominant allele

Having both alleles expressed equally in the phenotype of the animal.

 Phenotype

The observable physical or biochemical characteristics of an organism, as determined by both genetic makeup and environmental influences.

 Genotype

The genetic constitution of an organism, rather than being observable. Or A specific combination of alleles at one or more loci on a chromosome.