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|Guide to Leopard Gecko Morphs and Genetics
|Note: This guide is merely intended to be an explanation of the basic morphs and genetics behind Leopard Geckos. Some traits are controversial among Leopard Gecko enthusiasts due to their variability and subjective nature. The descriptions listed here, especially for polygenic traits, is simply my interpretation based on my experience as well that of other breeders in addition to a perceived “majority opinion”. This is not intended to be an all-inclusive list.
|Definitions: Simple Recessive: a trait that must be passed on by both parents for it to show up in the offspring. Animals that carry recessive traits but do not express them are referred to as being “het” (heterozygous) for that trait.
Polygenic: also known as “line bred” traits. Animals expressing certain desirable characteristics are selectively bred to each other in hopes of reproducing and improving those characteristics.
Co-Dominant: a trait that can be passed on by either one or both parents and be visible in the first generation of offspring. Co-Dominant traits can also yield a “Super” form if inherited from both parents.
Line-Breeding: breeding related animals together to intensify desired traits
Out-Crossing: breeding unrelated animals to introduce new traits or to increase genetic diversity and prevent genetic defects.
Phenotype: the actual, visible appearance of an animal
Genotype: the genetic composition of an animal, regardless of appearance.
Heterozygous: an animal that carries a recessive trait but does not express it
Homozygous: an animal expressing a recessive trait
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There are three known strains of albinism in Leopard Geckos that are incompatible with each other. Albinos are generally recognized by their lack of black pigment. Having red eyes is not a requirement in Leopard Geckos to be considered an albino. All three strains of albino are simple recessive traits.
Tremper Albinos are usually characterized by their light-colored eyes and tendency to have brownish markings on them. They were the first strain of albino Leopard Gecko discovered, and are also the most common of the albinos. Some variations of Tremper Albinos have pink eyes, but they may fade to a light silver color with maturity.
Rainwater Albinos are also known as “Las Vegas” Albinos. I use the two names interchangeably but they do describe the same strain of albino. Rainwaters tend to be the smallest of the albinos, and also have the darkest eyes. Many Rainwater albinos are lighter in color than the other albinos, but more color is being bred into them so it is not a definitive characteristic.
Bell Albinos are well-known for their light pink-colored eyes visible from birth through adulthood. Some of them tend to have a greater amount of small brownish spots, and some also have greater amounts of lavender coloring on them. Bell Albinos are the “newest” strain of albinism discovered in Leopard Geckos.
Patternless, short for “Murphy’s Patternless” is occasionally referred to as a Leucistic Leopard Gecko. This is morph is another simple recessive trait. They are known for their lack of pattern as adults, and as babies they have a unique spotted appearance–especially around the shoulder and head area. The color of a Patternless can range from grays to a greenish color over the whole body, but most will have a purple-gray tail. Through selective breeding, some breeders have managed to bring out the orange coloring at the base of the tail (“carrot tail”).
Blizzard Leopard Geckos are similar to Patternless specimens in appearance since they lack any of the typical spots and banding seen on other leopard geckos. Blizzards range from pure white to shades of gray, occasionally marked by varying degrees of a yellowish shine on their bodies. Blizzards do not have any visible pattern at any stage of maturity, and do not exhibit a noticeable amount of “carrot tail” like some Patternless Leopard Geckos. Blizzards can also fluctuate slightly in their darkness or lightness, and are thus referred to as “mood geckos” by some. Like the Albinos and Patternless, Blizzards are a simple recessive trait.
Patternless Albinos are Leopard Geckos that exhibit both the Patternless trait as well as one of the three strains of Albino. They look very similar to Patternless specimens, although their bodies are a shade of yellow instead of grey or green and their eyes are the color of the Albinos. They are a double recessive mutation, and can exist for all three strains of albino. Rainwater Patternless and Tremper Patternless Albinos are commonly available, but at this point Bell Patternless Albinos have yet to be produced to the best of my knowledge.
Blazing Blizzards exhibit both an Albino trait as well as the Blizzard trait, and are another double recessive mutation. Essentially, they look just like Blizzards except they lack any shades of grey. They are usually solid white geckos, but like the Blizzards, they can have varying degrees of a yellow overcast on their bodies. Both the Tremper Blazings and Rainwater Blazings are available on the market, but to date only one Bell Blazing has been produced.
Red Stripes, Bold Stripes & Jungles are considered by many to be polygenic traits, although some claim that stripes tend to act like a recessive trait. Jungles are characterized by their broken bands of pattern and no two are identical. Bold Stripes appear similar to Jungles, although the dark pigment runs only along the outside ventral surface of the animal’s body and tail. The amount of striping can vary, and some geckos will have a striped body without a striped tail and vice versa. There also exists a Reverse Stripe morph which has the darker pigment running down the spine of Leopard Geckos in one line. Red Stripes have been selectively bred to produce a mostly yellow or orange gecko with two reddish stripes down the dorsal surface of the Leopard Gecko. These stripes can vary in intensity, and frequently don’t show up until the gecko is six months old. Baby Red Stripes usually have a dark brownish color where the stripes will later come in, and adults’ stripes may fade back to a brownish color once they have reached maturity. The Red Stripe either has been, or is currently being introduced into the Albinos to produce albinos with the red stripes down their backs.
Hypomelanistic, Super-Hypo & “Baldy” are terms used to describe the lack of dark pigment on non-albino Leopard Geckos. A Hypomelanistic Leopard Gecko displays a greatly reduced amount of dark pigment over its body, although some spots may be present. A Super-Hypo is essentially a Hypomelanistic that completely lacks any spots on its body. “Baldy” is a term used to describe Leopard Geckos that also lack the pigment spots on their heads, although most if not all “Baldies” are also Super-Hypos. All of these traits are regarded as polygenic or line-bred, and usually don’t show up until the animal is maturing. Babies that exhibit spots or bands after hatching will loose those markings if they are a Hypo, Super-Hypo or “Baldy”.
Tangerine, “Carrot Tail” & “Carrot Head” describe varying degrees and locations of orange coloration on a Leopard Gecko. Animals labeled as Tangerine (or “Tang” for short) will have orange as a background color as opposed to the typical light yellow color seen on normal leopard geckos. The intensity of the orange color may vary from a yellow-orange to nearly red on some specimens. “Carrot Tail” is a term used to describe a Leopard Gecko that has an area of orange that starts at the base of their tail and continues toward the tail’s end. The amount of “carrot” varies from just a small band at the base of the tail to a solid orange tail seen on some extreme specimens. The usage of the term “Carrot Tail” is usually reserved for animals with at least 1/4 of their tail being orange. “Carrot Head” is a trait characterized by orangey spots on the top of a gecko’s head and is usually exclusive to Tremper Albinos. All of these traits are considered to be polygenic or line-bred.
Hybino Leopard Geckos are essentially the result of combining the recessive albino traits with the polygenic Hypo and Super-Hypo characteristics to produce Albinos with a solid or almost solid yellow to orange body color with varying amounts of carrot-tail and tangerine. These are referred to as “Sunglows” by some people. Hybinos can be created for each of the three strains of Albino, and can vary just as much as the Hypos and Super-Hypos.
Giant & Super Giant are traits believed to be co-dominant that affect the size of Leopard Geckos. This trait originated in Tremper Albinos and is usually not used for the other strains of albino even if the animal falls within the weight range depicted by the “standards” established for Giants and Super-Giants. The Super-Giants are the largest Leopard Geckos, with a record weight of 156 grams recorded.
Line-Bred Snows are Leopard Geckos that have been selectively bred to reduce the background color to a white or near-white color. An exceptional Line-Bred Snow would be black and white, with no noticeable yellow coloring on them. As their name suggests, Line-Bred Snows are a polygenic morph.
Mack Snow & Mack Super Snow are co-dominate morphs that reduce or eliminate the yellow and orange color seen on many Leopard Geckos. Mack Snows can be black and white, although some specimens show varying degrees of yellow after having been out-crossed. Mack Super Snows are characterized by their unique, high contrast black and white pattern and their solid black eyes. This pattern does not present itself on a hatchling Leopard Gecko, but usually develops within a month or so. Hatchling Super Snows are similar in appearance to blizzards. The Super form can be thought of as a recessive trait, since both parents must contribute a Mack Snow gene to produce Mack Super Snow offspring.
Various Morphs & Combination
Raining Red Stripes are a relatively new morph that resulted from combining a Rainwater Albino with a Red Stripe. Exceptional specimens have two unbroken orange-red stripes running down the back of the gecko and a fully-striped tail.
Mack Snow Patternless are Leopard Geckos that exhibit both the recessive Patternless trait as well as the reduction in yellow, orange & red pigment from the Mack Snows. As hatchlings and juveniles, they show the slightly spotted pattern seen on young Patternless, but this fades away as the geckos mature.
Mack Snow Albino is the result of combining one of the three types of Albino with the Mack Snow gene. As hatchlings, the yellow color of the albino is replaced with white, but as the gecko matures some yellow starts to appear, resulting in a pastel colored Albino.
Mack Super Snow Albino is basically the Mack Super Snow version of the Mack Snow Albinos mentioned above. Like the Mack Snow Albinos, these can be created for any of the three types of Albino. They exhibit the same pattern as a Mack Super Snow, but the black is replaced by shades of beige or tan. Mack Super Snow Albinos have solid colored eyes which are very dark on Tremper and Rainwater specimens, and solid bright red on Bell Albino specimens.
A.P.T.O.R., R.A.P.T.O.R. & “Eclipse” are essentially three variations of the same Tremper Albino morph. A.P.T.O.R. stands for Albino Patternless Tangerine Orange, and R.A.P.T.O.R denotes specimens with red eyes. The “patternless” trait affecting these morphs is not compatible with the Murphy’s Patternless. The “Eclipse” refers to a non-Albino variation of this morph and is occasionally used to refer to Leopard Geckos with “Snake Eyes”. More information can be found at www.LeopardGecko.com
“Snake Eyes”, as pictured here are basically Leopard Gecko eyes that have solid black areas in their irises. Many such specimens will have one or both eyes half black, while others will show anywhere from 1/4 to 3/4 of their eyes solid black. The genetics behind this trait are still suspect, but it does seem to occur the most often with Blizzard and R.A.P.T.O.R morphs. Some breeders have also produced albino animals with “Snake Eyes”. Occasionally the term “Eclipse” is also used to describe this trait.