Crested Gecko Genetics: What Is Known and What Is Not

The field is much less settled than the morph market suggests. Science has a sequenced genome, a chromosome count and one conference abstract on sex chromosomes. It has no published gene for any morph.

The list of names lives on the crested gecko morph index, so this page covers only what is proven and what is not.

What is proven about crested gecko genetics

The crested gecko is Correlophus ciliatus. A 2012 Zootaxa revision using mitochondrial ND2 and nuclear RAG1 sequences showed that the old genus Rhacodactylus was not a single natural group. It resurrected Correlophus for the crested gecko and its close relatives.

The karyotype is 2n = 38, with biarmed and acrocentric chromosomes typical of New Caledonian geckos. A 2024 bioRxiv preprint put the genome at about 1.65 Gb, with GC content near 45% and heterozygosity near 0.51%. The team sequenced a single female embryo.

The peer reviewed version appeared in G3 in 2025. It reports a 1.66 Gb assembly with a scaffold N50 of 109.97 Mb and 19 chromosome scale scaffolds. That count is the haploid number and matches 2n = 38.

The paper does not identify genes for color, pattern or morph traits. For crested gecko genetics, that means the raw material for a future gene search now exists, but the search has not been reported.

The preprint title also states that the species cannot regenerate its tail. That is a fixed trait of the species and has nothing to do with morph genetics.

A single female embryo also limits what the assembly can show. One genome cannot reveal which variants separate one morph from another. Comparing many animals with known appearance and pedigree would be needed, and no such study has appeared.

How sex is determined

The sources disagree here. Animal Diversity Web states that sex in this species is environmentally controlled. It reports that warmer incubation gives more males and colder incubation gives more females.

A 2021 abstract from Marquette University researchers points the other way. Its title describes ZZZW sex chromosomes in the crested gecko, and it describes a female heterogametic system. The authors used RNAseq data and found that Z linked genes did not appear to be upregulated in females relative to males.

Neither genome paper addresses sex determination, and no full peer reviewed paper has yet settled the question.

Treat the sex determination mechanism as unresolved, with genetic sex chromosomes now the better documented claim. Sex chromosomes matter for breeding because they would make the sex ratio independent of incubation temperature.

Keepers who incubate at different temperatures to steer sex would then be acting on a false premise. Until a full paper confirms one system, no incubation rule should be presented as proven.

What the hobby reports and what is untested

Breeders describe crested gecko morphs in the same vocabulary used for other reptiles: recessive, incomplete dominant, dominant and polygenic. None of these labels has a published genetic test behind it for this species. The wild type only gives a baseline: ADW describes patternless, tiger and white fringed animals, and notes extra variation in captivity.

The table below lists the trait names most often quoted. Each row carries the hobby label, because no university, museum or veterinary source confirms any of the modes.

The pattern traits are the weakest claims. A polygenic label means many genes each add a small effect, so offspring vary and results are hard to predict. Without a mapped gene, that description is an observation about breeding outcomes and not a proven mechanism.

How combinations work in a hobby model

If a breeder pairs an incomplete dominant trait with a normal animal, the reported result is about half carrying one copy. If two carriers are paired, the reported result is a quarter with two copies, called a super form. A recessive trait is reported to need two copies to show, so carriers look normal.

These ratios are the textbook expectation, not measured crested gecko data.

Clutches are small, usually two eggs, so a single pairing tells you very little about the ratio. Only many clutches over several seasons can test a claimed mode.

Records that list every egg, including infertile ones, would be needed. A published pedigree study of this kind does not exist for the species yet.

For the general rules of Punnett squares, read the guide to morph genetics rather than treating this page as a manual.

To model a pairing, the crested gecko morph calculator uses these reported labels as a hobby model.

Health linked traits

Breeders report that the super form of Lilly White is lethal. They also report that super cappuccino animals have health and viability problems. Both are hobby claims, reported by breeders and not independently tested, and no peer reviewed or veterinary source confirms either one.

The practical rule is caution, and it costs a breeder very little. Pairing two animals that both carry a reported incomplete dominant trait may produce a super form that breeders say does not thrive. Choosing a mate without that trait avoids the reported risk.

Also, some breeders discuss eye or skin problems in particular lines. That is anecdote as well. If an animal shows swollen eyes, poor shedding or weak growth, see a reptile veterinarian rather than relying on morph folklore.

Color change is not genetics

Keepers describe a crested gecko as fired up or fired down when its color looks stronger or paler. That is a physiological change in the skin, driven by pigment cells, not a genetic trait. No study has measured it in this species, so treat any specific rule about its timing as keeper observation.

For what the base colors look like, see the page on crested gecko colors.

For the species overview, go to the crested gecko care guide.

How to read a claim about crested gecko genetics

• Look for a named study. A genome paper does not count as a morph paper.
• Check whether the seller states a mode as fact or as a report.
• Treat “proven” claims about a super form with suspicion unless a paper is cited.
• Expect the polygenic label on any pattern trait.
• Check the lineage for a trait before pairing two carriers.

The broader picture across species is on the reptile morphs overview.

Related geckos are covered on the gecko morphs page, which shows which species have tested genes.

Frequently Asked Questions

Has the crested gecko genome been sequenced?

Yes. A chromosome level assembly was published in G3 in 2025 after a 2024 preprint. It has 19 scaffolds at chromosome scale and an N50 of 109.97 Mb.

Is there a gene test for Lilly White or cappuccino?

No gene test has been published for either trait. The inheritance modes quoted for both are breeder reports. A tested marker would need a published gene, and none exists yet.

Are crested geckos temperature sexed?

Animal Diversity Web says yes, with warmer incubation giving more males. A 2021 conference abstract instead describes ZZZW sex chromosomes. The question is not resolved in the published record.

How many chromosomes does a crested gecko have?

The karyotype is 2n = 38, so 19 pairs. That is typical of New Caledonian geckos. The G3 assembly resolves 19 chromosome scale scaffolds.

Why do breeders say a trait is polygenic?

Offspring from the same pair vary widely, which suggests many genes. That is an inference from breeding results. It has not been mapped in a study.

Can I trust a super form warning?

Treat it as a precaution. The lethality and health claims are hobby reports, but they come from many breeders and cost little to respect.