Tiger Crested Gecko Breeding: What Polygenic Really Means
Tiger crested geckos are polygenic, not Mendelian. Learn what that means for your pairing outcomes, pattern selection, and long-term breeding strategy.
A breeder at a 2023 regional reptile show sold a pair of well-fired chocolate Tigers for $340 combined. The buyer went home, paired them, and got a clutch of six. Two looked like decent Tigers. Two looked like flame animals with irregular markings. One looked patternless. One looked like a dark buckskin with a smudge across the back.
The buyer was not cheated. The seller was not lying. Both parties just didn't understand what polygenic means in practice.
So here is the question this post answers: if Tiger is a real, consistent pattern in the hobby, why does pairing two Tigers produce such unpredictable offspring?
Published 2026-06-12.
TL;DR
- Tiger pattern in crested geckos is polygenic, so Punnett squares do not apply and two Tiger parents will not produce consistent Tiger offspring.
- Pattern quality responds to selective pressure over multiple generations, not a single pairing.
- Tiger sits on a continuum with Brindle, animals that fall in between are sold as Tiger/Brindle (T/B), a legitimate category.
- Foundation Genetics models Tiger as a dominant trait present in every crested gecko at varying intensity, which means breeding it out is not possible, only amplifying or suppressing it.
- Stacking Tiger with base color traits like Red Base or Olive produces the most dramatic fired-up contrast, but the combo reads differently in fired-down photos.
Frequently asked questions
Are tiger crested geckos a proven Mendelian morph?
No. Tiger is a polygenic trait, meaning it is controlled by many genes with additive effects, not a single locus. You cannot use a Punnett square to predict Tiger offspring ratios. Pattern quality improves through consistent selective breeding over multiple generations.
What is the difference between Tiger and Brindle in crested geckos?
Tiger shows relatively clean, parallel horizontal bands across the dorsum. Brindle shows more irregular, broken, or overlapping dark markings across the same area. Both sit on the same polygenic continuum, and animals that fall in between are sold as Tiger/Brindle (T/B). The distinction is a sales category, not a genetic switch.
Will pairing two Tiger crested geckos produce Tiger offspring?
Not reliably. Because Tiger is polygenic, two Tiger parents produce a spread of offspring ranging from near-patternless to bold Brindle. The average quality shifts toward the parents over many clutches and generations, but individual clutches will vary widely. Consistent selection over 3 to 5 generations is needed to meaningfully tighten expression.
Why does my Tiger crested gecko look different during the day vs. at night?
Tiger banding is melanin-dependent. At night (fired up), melanophores spread melanin granules and the bands become dark and sharp. During the day (fired down), melanin clumps and the bands fade. Evaluate Tigers and photograph them for breeding records only in fired-up state.
What base colors work best with Tiger pattern?
Red Base and Olive provide the most contrast with Tiger banding. A saturated red base makes the dark Tiger bands stand out dramatically when fired up. Olive Tiger carries an unusual earthy quality that holds across fire states. Chocolate Tiger is rich in texture but lower in contrast because both the base and bands are dark.
Can you breed Tiger out of a crested gecko line?
Under the Foundation Genetics model, Tiger expression is present at some level in every crested gecko and cannot be fully removed, only suppressed. What breeders call patternless animals are animals where Tiger expression is overwhelmed by modifiers, not animals with zero Tiger genetics.
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