Leopard Gecko Morphs & Genetics

What is a leopard gecko morph?  The short answer is that morphs are a result of genetic breeding, which produce variations of colors and patterns of a leopard gecko’s skin. (The same techniques are used for other lizards and snakes as well.)

Essentially, a leopard gecko morph is the same gecko with a different paint job, achieved through genetic combinations.  Think of morphs as designer or “fancy” leopard geckos. The higher price of some leopard gecko morphs represents rarity of the breeds and the genes the gecko is carrying. 

Some morphs make take several generations to produce, depending on the gene combinations and whether various desirable traits are recessive or dominant.

To learn about what makes a leopard gecko morph, we’ll venture into the topics of genetics and heredity.

Genetics and Traits

The first stop on our journey is some basic genetic terms and vocabulary.  This will be helpful  not only to understand how the science works, but also to understand what you are getting when evaluating a leopard gecko morph.  Breeders will often use these terms when describing their latest morph masterpiece.

• Trait: Specific genetic characteristic  (e.g. eye color)
• Gene:  A unit of heredity containing information about a specific trait that is passed from parent to child.   Each  gene is  made up of two alleles, which combine to determine which characteristic is present
• Allele: One of two (or more) alternate forms of a gene that occupy the same position on a chromosome.  For each gene, two alleles are present.
• Dominant: An allele that gives favor for its trait.  A dominant trait can be passed along to an offspring from a single parent
• Recessive: An allele that manifests only in absence of a dominant allele.  The same recessive allele must be passed by both parents in order to express the trait
• Co-Dominant: Represents the presence of one or two dominant alleles. Two Dominant alleles will yield a “super” variety  of the trait.
• Genotype: Combination of genes contributing to the presence of a trait
• Phenotype: Outward appearance resulting from the combination of genes contributing to the presence of a trait
• Homozygous: Two alleles of like kind contributing towards a gene
• Heterozygous: Two alleles of different kind contributing towards a gene.  The dominant will be visually present while the recessive gene is still carried.  This is often shortened to “het” when discussing morphs.

Breeding for Morphs

Breeders will mate leopard geckos with selected traits in hopes of producing offspring of a particular genotype. Parents have a 50% chance of passing a particular trait along to offspring.

Dominant genes (as their name implies) have a higher chance of contributing to the genotype. Producing offspring with recessive traits is a numbers game, with a bit of luck and change.

Still, we can predict the probability of the offspring a leopard gecko pair may produce. How? Science!

Fun with Punnett Squares

Named after Reginald C. Punnett, the Punnett Square is a diagram used to predict the probability that an individual trait will be passed to an offspring, based on the genes carried by both parents.  In humans this would be something like eye color or hair color.  An example in leopard gecko morphs, traits would include features like skin pattern and color.

In a Punnett Square, dominant alleles are shown as uppercase, while recessive are represented as lowercase.  Each square in the grid represents a gene, which is comprised of two alleles; one from each parent. 

Let’s look at a simple example of a “Normal” leopard gecko mating with an albino. Normal is a dominant trait, and would be represented by NN, while albinism is recessive and would be represented by aa.

This combination would always produce Na, which would be a “normal” gecko that would be heterozygous for albinism, or het albino. The dominant allele would determine the genotype. This means the offspring would appear normal, though they still carry the albino gene.

So, to take this a step further, what if two geckos with these genes (Na) mated. Now things get interesting, and this is where selective breeding becomes a strategic game of chance and probability. The normal geckos with het-albino combination would look like this:

So, the probability of the offspring would be:

• 50% Normal with het-albino (Na)
• 25% Normal (NN)
• 25% Albino (aa)

What types of morphs are there?

Morphs started coming into vogue in the mid 1990’s as breeders experimented with these concepts in captive selective breeding.

In the decades since, leopard gecko breeders have developed all kinds of combinations to bring out different colors, stripes, spots, eye color, and size.

Below is a list of just some of the breeds and terms you may come across when browsing or discussing leopard gecko morphs:

• Albino
  • Leopard gecko albinos have a lack of black pigment, as opposed to white skin and pink eyes normally associate albinism in other species.
  • There are 3 distinct types of albino leopard geckos: Tremper, Bell, and Rainwater (also referred to as “Las Vegas“)
• Bandit & Halloween Mask
  • Bandit leopard geckos have distinct bold band between their nose and eyes, resembling a bandit’s mask
  • Bandit morphs usually have less spots on their heads in favor a a few bold stripes or markings
• Blizzard
  • Blizzard leopard geckos lack spots, banding, and patterns and usually range from white to gray in color
• Eclipse
  • Eclipse geckos are notable in that their eyes are solid black
  • When crossed with the Tremper Albino, there is a chance of producing a leopard gecko with solid red eyes
• Giant & Super Giant
  • Larger than your average leopard gecko, with males up to 110 grams and females up to 90 grams
• Godzilla
  • The largest leopard geckos available
• High Yellow
  • A fairly common morph with fewer back spots and a deeper yellow color
• Mack Snow
  • Mack Snow leopard geckos have little or no yellow/orange coloring
• Patternless
  • As the name implies, geckos with this trait lack the typical spotting and patterns usually associated with leopard geckos
  • Different from Blizzards, Patternless leopard geckos often have orange coloring at the base of the tail, often referred to as “carrot tail”
• R.A.P.T.O.R & A.P.T.O.R
  • Red-Eye Albino Patternless Tangerine Orange
  • An APTOR is a RAPTOR without red eyes
  • Bred through a combination of the Eclipse, Patternless, and Tremper Albino
• Stripes & Reverse Stripe
  • Have stripes rather than spots
• Tangerine
  • High concentration of orange coloring
  • Also referred to as “Carrot Head” or “Carrot Tail”, depending on where the orange color is concentrated.

For more on leopard gecko morphs, check out our related post, What kind of leopard gecko morph breeds are there?

Leopard Gecko Alleles

There are a number of traits that can be passed on and manipulated through selective breeding. Here are a few examples of dominant and recessive alleles. Remember, for a recessive allele to be visually present, it must be passed on from both parents.

Recessive Traits
Albino (Tremper, Bell, Rainwater)
Patternless
Blizzard
Eclipse (solid eye color)

Dominant Traits
Normal
Giant

Co-Dominant Trait
Snow

Many of these traits are recessive, and have a lower chance of visually manifesting. As we saw in our Punnett square example above, two het-albinos had only a 25% chance of producing albino offspring. This is why some particular combinations can command such high prices.

Where can I find leopard gecko morphs?

The leopard geckos you’ll find at most pet stores will be mainly ‘normals,’ meaning the traditional yellow coloring with black spots. To find the more exotic colors and patterned morphs, you’ll need to find a breeder. You may be fortunate enough to have one local, or may be able to visit a reptile expo or show where there are usually breeders.

You can find them online as well. Leopard Gecko Habitat is affiliated with CBReptiles.com, where you can find all kinds of leopard gecko morphs (and other reptiles as well!) You can find what they have available here.

Further Reading

For a more comprehensive look at morphs, it’s worth checking out Leopard Geckos: the Next Generations by Ron Tremper.  The Tremper Albino leopard gecko morph bears the author’s name.  The book features over 200 photos  and offers a great perspective on what some of the genetic combinations will yield, and what you can expect the various morphs to look like.