Snow (Mack) Leopard Geckos

A leopard gecko's banding loses its yellow and turns into a cooler black-and-white palette with the Mack Snow. The look of Mack Snow comes from one copy. Super Snow is produced by two copies and is distinct enough to identify by eye.

Appearance

The usual yellow-and-black pattern is replaced by a striking swap where Mack Snow hatchlings have white bands between black ones. During the first year or so, this white fades toward yellow. This fade varies from gecko to gecko because some keep visible banding into adulthood while others settle into a paler grey-yellow. Super Snow is a white to pale grey gecko with fine black speckling in place of banding and solid black eyes with no visible iris pattern, which is made by two copies of the gene. At a glance, those eyes are the most reliable way to tell a Super Snow from a single-copy Mack Snow.

Genetics

Snow (Mack) is incomplete dominant. Because one copy gives the Mack Snow look, pairing two Snow (Mack) animals can also produce the homozygous Super Snow (Mack). This is the catalogue's other family row and a visually distinct line in its own right. The hobby's looser word for this inheritance is co-dom, which breeders often use to shorten the mode. John and Amy Mack of Reptiles by Mack produced the original animals, and breeding them on gave Super Snows, Mack Snows and normals. To produce Super Snow offspring, Snow (Gem) and Snow (Tug) have each been crossed with Snow (Mack). This is why some breeders treat the snow lines as potentially allelic, even though each keeps its own catalogue row. Mack Snow is also the one leopard gecko line that has not been shown to follow the incubation-temperature sexing every other morph responds to. The gene has named combinations including Galaxy, Universe, Creamsicle and Snow Glow.