Highway Crested Geckos
A crested gecko with the Highway gene has a creamy back, quieter sides and a tail that marks it out. Geckos carrying two copies have shown poor health and reduced nostrils, so breeders work the gene one copy at a time.
About the Highway gene
The Highway gene for crested geckos makes the back paler and softens the side patterns to create a cleaner animal. This cleaner look is the draw. Because the two-copy form has health problems, breeders work it as a single copy and pairing for it is widely discouraged.
Appearance
The tail displays the clearest marking of the gene, making it the most dependable spot to confirm one. A Highway has a dorsal that is white or creamy, and it is paler and heavier than a normal's. Because the gene tends to eat into the muted lateral pattern, the flanks look less busy and cleaner.
Genetics
Highway is an incomplete dominant gene. One copy shows, and an animal with two copies is a Super Highway. Many listings call it co-dom, which is the looser hobby word for this same behaviour. Breeding results place Highway as a third allele in the group containing Cappuccino and Sable, though this is still a working model rather than a settled one. It matters for pairings: a Highway bred to a Cappuccino or a Sable can produce animals carrying two alleles from the group. Breeders advise real caution before setting those pairings up.
Known issues
The issue is found in the two-copy form, Super Highway, rather than in a single-copy Highway. Because Super Highways show poorer health and reduced nostrils in the same way as Super Cappuccino, breeders who work the gene advise against pairing two Highways to produce them.