Axanthic Crested Geckos
Axanthic strips the red and yellow from a crested gecko and leaves black, white, grey and brown across its pattern. Several lines exist and most work together, but Obscurial is treated as its own morph, so find out which line you are buying into before you pair.
About the Axanthic gene
The Axanthic gene in crested geckos stops the animal making red and yellow pigment. Only white and melanin remain, so a visual reads in silver, grey, black and white instead of the creams, oranges and reds the species is usually sold on. Keepers buy it for exactly that: a monochrome gecko with every scrap of pattern on show.
Appearance
The gene leaves melanin alone and acts only on the xanthophores, the cells for yellow and red. Not every xanthophore is lost, so some animals keep a faint wash of red or yellow, and a trace of warmth does not on its own rule a gecko out. The base underneath still matters: black stays black, while yellow and red bases come out in red-tinged tones and browns. A visual is usually black and white, or heavy in brown.
Pattern carries straight over. Pinstripe and Harlequin axanthics show white pattern on a black to brown base, though much of the white has tended to fade in Harlequin Axanthics. Phantom Axanthic gives a very dark animal that keeps its usual white pattern areas, and Lilly White Axanthic carries more white than any other pairing with the gene.
Genetics
Axanthic is recessive, so a het looks like any other crested gecko. The family is sold as Axanthic, Het Axanthic, 50% Het Axanthic, 66% Het Axanthic and Pos Het Axanthic. Brian Butler of Altitude Exotics in the US bought the trait when it first turned up in the UK. Several lines appeared within a short time of each other, including Obscurial, MSL and Altitude Exotics. They seem compatible, most likely because hets had spread through the hobby before anyone knew what they carried. Matt Karwacki's Lizard Wizard Reptiles line, Obscurial Axanthic, is a separate morph on bask. The breeder believes it is compatible with the others but has not test-bred it against them, so ask the seller which line an animal comes from before you plan a pairing. You may also see the gene called Genotype X.