Quad-stripe Crested Geckos
The pattern on a quad-stripe crested gecko is read as four stripes instead of two because it has a raised pinstripe on the back and an extra line on each flank. Note how far these flank lines stay unbroken. Some geckos have them for the length of the body while others show only dashes.
About the Quad-stripe gene
A quad-stripe crested gecko has four stripes along its back instead of two because a second pair of lines appears along the flanks. This is a pattern trait rather than a single-gene mutation. It is produced by breeding toward the most continuous and strongest striping over several generations. What a buyer pays for is how unbroken and clean that pattern holds, instead of a genotype or a colour.
Appearance
The pinstripe is the base. When a quad-stripe is added, a second pair of lines appears along the middle of each flank between the front and back legs. This makes the pattern look like four stripes instead of two. The tail, belly and head remain unaffected. The distance the flank lines run varies a great deal. Some geckos have an unbroken line the length of the body. Others have only broken dashes or porthole-like spots along the flank and are sold as broken quad-stripes.
Genetics
The Quad-stripe is a polygenic trait. Like other crested gecko pattern traits that are fixed into a line, breeders build it up over generations by selecting for the most continuous and strongest striping. A separate het or super form does not exist. You will see it listed as Quad-stripe and Pos Quad-stripe. Rather than other genes, the pattern is combined with colour and pattern morphs.