Predicting the outcome of leopard gecko breeding can be a complex task involving Mendelian genetics. This calculator allows you to select the genetic traits of both the male (Sire) and female (Dam) to estimate the probability of specific morphs in their offspring.
Sire (Male)
Dam (Female)
Understanding Leopard Gecko Genetics
Leopard gecko (Eublepharis macularius) breeding has evolved from simple hobbyist interest into a sophisticated study of genetics. To use a morph calculator effectively, one must understand the three primary types of genetic inheritance: Recessive, Dominant, and Co-dominant (Incomplete Dominant).
Recessive Traits
Recessive traits require two copies of the gene (one from each parent) to be physically expressed. If a gecko has only one copy, it is known as a "Het" (Heterozygous) for that trait. Common recessive traits include:
- Tremper Albino: The first albino strain discovered.
- Blizzard: A patternless gecko that is usually white, grey, or yellow.
- Murphy Patternless: Often born with spots that fade into a solid body color.
Co-Dominant Traits
Co-dominant traits, like the Mack Snow, behave differently. A gecko with one copy of the gene looks different from a "Normal," and a gecko with two copies (Homozygous) looks different from the single-copy version. For example, breeding two Mack Snows can result in a Super Snow.
The Importance of Strain Compatibility
One of the most critical rules in leopard gecko breeding is never to cross albino strains. Tremper, Bell, and Rainwater albinos are located on different loci. Crossing them results in "double-het" offspring that look like normal wild-type geckos, which can pollute genetic lines and cause confusion for future breeders.
How to Use the Calculator
To get started, simply select the visual traits of your breeding pair. Note that this basic version of the tool assumes the parents are homozygous for their visual traits (unless they are Mack Snows). In professional breeding, you would also account for "Hets," which adds another layer of mathematical complexity to the results.