Leopard Geckos, as we know them in the pet trade, are genetic mutts! I don't mean to sound harsh here, but it helps a lot to realize this. Most of the Leopard Geckos available today can be traced back to large numbers of wild-caught specimens imported in the late 1970s. At that time, little scientific information was available about these geckos and most hobbyists had no idea there were several closely related species and subspecies among the imports. The result: many forms were bred together and today we have a genetic mess on our hands. That's the downside, the upside is that we have a lot of genetic variability present as a result!

Leopard Geckos In The wild:
The Leopard Gecko (Eublepharis macularius) as taxonomists currently recognize it, consists of five subspecies found in Afghanistan, Pakistan, Western India (Rajasthan, Ajmer, Madar foothills), Iraq and Iran. They are:

• Eublepharis macularius fasciolatus GÜNTHER 1864

• Eublepharis macularius afghanicus BÖRNER 1976

• Eublepharis macularius macularius BLYTH 1854

• Eublepharis macularius montanus BÖRNER 1976

• Eublepharis macularius smithi BÖRNER 1981

Additionally, four closely related species are currently recognized. At least one of these was formerly included in the E. macularius complex and has undoubtedly contributed it's unique genetic make-up to the mix currently kept in captivity as well. They are:

• Eublepharis angramainyu

• Eublepharis fuscus

• Eublepharis hardwickii

• Eublepharis turcmenicus

What does all this mean? Well, it means that today's pet Leopard Geckos are subject to an enormous amount of natural variation. In addition, several true genetic traits have been uncovered. These, combined with the natural variation, have led to the 'naming' of innumerable morphs. Many are nothing more than natural variation, and will not breed true when crossed to others with differing appearances. Others are a bit more complex and breed true, but with variation.

Naturally Occurring Variation
Having a wide natural range, the Leopard Gecko exhibits a lot of variation in the wild. Some types are more or less 'standardized' in appearance, with breeders attempting to further refine and purify these strains. Often these distinctive types are used to alter the effects of other mutations resulting in some rather distinctive lines of Leopard Geckos.

Note that these naturally occurring variations are not single trait mutations, but rather a polygenic appearance derived from innumerable small alleles all having a minor impact on the overall appearance of the gecko. Thus, specimens cannot be heterozygous for these traits. It can be best be compared to raising champion race horses, breeding the best specimens together will generally result in the best appearing offspring - but none could ever be listed as heterozygous for "Secretariat" or "Sea Biscuit"

Some commonly used names for these variations include:

• Normal
  What exactly is 'normal' for a Leopard Gecko? Well, as discussed above, there is an enormous amount of 'normal' variation! But in today's marketplace, the name is used to designate a typical, average, everyday, Leopard gecko. The specimen illustrated here could be considered a normal Leopard Gecko. Some specimens may have fewer, larger spots.
   

• High Yellow
  This was the first of the so-called 'designer' morphs of Leopard Gecko. It is nothing more than a normal Leopard Gecko that has been selected for reduced black spotting and lots of yellow pigment. High Yellow specimens can be found frequently in almost any breeding of Leopard Geckos. They are representative of one extreme of the naturally occurring variation found in captive populations. Specimens cannot be het for High Yellow.
   

• Pastel
  Pastels are another representative of one extreme of the naturally occurring variation found in captive populations. Lacking any true black pigments, the black is replaced with pale tan, and most are of extremely pale coloration. Some also have lavender bands, especially when young. Specimens cannot be het for Pastel.
   

• Jungle
  An aberrant pattern of broken stripes, usually extending onto the tail. Some will form full-length stripes, and many breeders sell these as 'Striped'. Not all Jungles breed true, as this trait appears dependent upon several mutated alleles. These must be present to produce a Jungle, but specimens with mutated alleles may also appear normal - or combinations of normal & jungle patterns. When breeding jungles, you may get a variety of patterns - selection plays almost as big a role here as genetics and caution should be exercised with regard to specimens sold as heterozygous, as the results obtained from breeding them will not follow expected Mendelian rules of inheritance.
   

• Snow
  Perhaps the most extreme selectively bred example derived from the naturally occurring variation found in captive populations. Lacking almost all yellow pigments, the best of these can appear nearly snow white with even the black spotting greatly reduced. However. many will develop at least some yellow pigmentation as they mature. Specimens cannot be het for Snow.
   

Single Genetic Trait Leopard Geckos
To fully understand the genetic makeup of any given type, it is important to understand that there are currently seven loci known to harbor mutated alleles in Leopard Geckos. Additional alleles/loci will most certainly be identified as time goes by and research is performed on suspected new mutations. All of the Leopard Geckos presented in this section are affected by a single mutated allele.

• Murphy Patternless
  This was the first true simple recessive genetic mutation to be produced. After over twenty years of breeding Leopard geckos in captivity, imagine the surprise of finally getting a true mutation! Why did it take so long? Well, Leopard Geckos have small territories and probably do not travel far in search of mates in the wild. So they seem to have a natural resistance to inbreeding.
  
  Originally marketed as 'Leucistic' and sometimes still labeled as such by some breeders. Today the name Murphy Patternless is gaining usage to help in distinguishing them from other lines of patternless appearing geckos entering the marketplace.
   

• Tremper Albino
  The second simple recessive mutation to occur was a beautiful form of albinism. Popularized and brought to market by Ron Tremper, this line is now referred to as the 'Tremper' Albino, to differentiate it from the other types of albinos that have since popped up in the market place. It was the first of the albinos to be produced. Note that the different types (Tremper, Las Vegas, and Bell) have been given different names for a reason - they are NOT compatible when bred together. Maintain each line of albino separate and keep good records, or a genetic mess may result!
  
  Some keepers believe the three types of albinos can be separated visually based on overall appearance. This is not accurate! There is much variation in overall appearance of these albinos, based on the naturally occurring variations present in all populations. As a result, a near complete overlap in appearances is present within large samples of albinos, rendering accurate visual separation of the types impossible.
  
  As mentioned above, the overall appearance of any given albino specimen can be affected by a number of factors. Many breeders are carefully selecting for specimens with a given appearance and crossing their albino specimens to
  selectively bred color variations to create a host of new 'morphs'. New names for such specimens are created almost daily by breeders in an effort to gain a foothold in the marketplace. Most of these name appear and then quickly vanish, but several seem to persist, based on acceptance by the public and common usage. Commonly seen examples include: Jungle Albino, Tangerine Albino, and Chocolate Albino.
   

• Las Vegas Albino
  The second strain of Albino, not genetically compatible with the Tremper or Bell lines. Many folks believe these to be superior to the Tremper line as they tend to remain lighter in color. This is the result of an aggressive marketing campaign by the originator of the strain! Both types are absolutely lovely and when selected for appearance based on the naturally occurring variations which shine through the albinism, the results can be stunning with any of the albino types. Sometimes referred to as the 'Rainwater' Albino, after the originator of the strain.
   

• Bell Albino
  The third strain of Albino, also proven to be non-compatible with other known strains. Mark Bell, a very respected breeder in the industry, was fortunate to have yet another form of albinism pop up in his collection. Like the other types, it has been proven a simple recessive trait.
   

• Blizzard
  Completely patternless, with only faint traces of yellow coloration remaining, these are quite possibly true leucistic Leopard Geckos. A high-yellow variant is often referred to as 'Banana', although this term is more properly applied to specimens double homozygous for Murphy Patternless and Blizzard. Another simple recessive genetic trait.
   

  Eclipse
  A relatively new trait which affects the eyes only, and can be combined with any pattern appearance. Quality specimens homozygous for the trait exhibit deep solid black eyes, or solid red in the case of albinos. Some specimens from this line have only half the eye, or half of one eye, affected and are termed "snake-eyed". It is not clear precisely why at this time. Our experiments have indicated this trait is inherited in recessive fashion. Solid-eyed Eclipse specimens when bred to normal eyed specimens have only produced normal eyed specimens, "heterozygous" for the trait in the F1 generation. As expected, when breeding these "hets" together a variety of types is produced in the F2 generation, including some normal-eyed, some solid-eyed and many snake-eyed. It is at this point that the conventional model of heterozygous behavior breaks down. Breeding together specimens from the F3 generation yields unexpected results, with some pairings of snake-eyed specimens capable of producing solid-eyed specimens, yet other pairings do not ever seem to do so. The simplest and most logical explanation for this pattern of inheritance is that the Eclipse trait is actually controlled by alleles at two loci and thus the "hets" produced in the F1 generation described above are in fact "double heterozygous" for the two traits needed to create solid-eyed specimens. If this theory proves correct, breeders will need to understand that normal-eyed specimens may thus be heterozygous for either or both of the alleles, and that snake-eyed specimens are likely homozygous for one allele and may or may not be heterozygous for the other! While this situation would precisely explain some of the results many have reported thus far, it is far from certain at this time. Solving this riddle will take time, and it is mentioned here only to explain the often undesirable results keepers obtain when breeding snake-eyed specimens or heterozygous specimens.
   

• Giant
  A unique mutation uncovered by Ron Tremper. This mutation is unique in that it has no effect on color, but is instead the first known mutation controlling overall size and body configuration. Additionally, it has recently proven incomplete dominant - the first such mutation discovered in Leopard Geckos.
  
  Sadly, the true genetic nature of this mutation was not fully understood at first and this has caused quite a bit of confusion surrounding them in the marketplace. Originally thought a simple recessive gene, with 'heterozygous' specimens sold for rather high prices during the first years. Being a codominant mutation, there is no such thing as a 'het' in the classic sense, leading many breeders working with 'hets' to believe the mutation was not real. The simple truth was that many of their specimens were in fact completely normal!
  
  Since the mode of inheritance of codominant mutations is so poorly understood by most Leopard Gecko keepers, I'll attempt to explain it here in some detail:
  
  With regard to the Giant mutation and it's effect on appearance, Leopard Geckos can exists in three possible genetic states: Normal (no mutated alleles present), Giant (one mutated allele present) and Super Giant (two mutated alleles present).
  
  1) Normal specimens (no mutated alleles present), are of course, just that - completely normal in every way. They exhibit no characteristics of the Giant mutation, nor can they be heterozygous for Giant.
  
  2) Giant specimens (one mutated allele present) can get somewhat larger than normals, although this varies, and many exhibit the elongated 'lanky' appearance caused by the mutated allele. Strictly speaking, these are in fact heterozygous and typical rules of inheritance apply when breeding them - the only thing different here is that such heterozygous specimens can now be spotted visually, something that cannot be done with simple recessive mutations!
  
  3) Super Giants (two mutated alleles present) show even more of these effects, growing quite large (specimens weighing over 180gms are known) and exhibiting such an elongated and lanky appearance that even the snout is noticeably longer and more pointed.  These are in fact homozygous, and typical rules of inheritance apply when breeding them.
  
  It must be mentioned here that there is a range of variation in the overall effect caused by this mutation, and it is near impossible to separate the various types visually with any degree of certainty. In a mixed bag of all three types, most of the supers can be quickly separated, as can many of the normals. But the remainder will consist of a mixture of specimens that could be either normal or Giant; Giant or Super Giant.
  
  Thus, it is important to fully understand the mode of inheritance as knowledge of the predicted outcomes of various crosses can greatly simplify sorting out the results. Perhaps the following will help:
  
  Normal x Normal yields all Normal offspring.
  Normal x Giant yields half Normal, half Giant offspring.
  Normal x Super Giant yields all Giant offspring.
  Giant x Giant yields 1/4 Normal, 1/2 Giant, 1/4 Super Giant offspring.
  Giant x Super Giant yields 1/2 Giant, 1/2 Super Giant offspring.
  Super Giant x Super Giant yields all Super Giant offspring.
  
  Additional outside factors can also influence the growth and size of these specimens. Specimens out-crossed to various other morphs can be affected by the size typically achieved by that particular strain (some morphs can run larger than others, and this has it's effect too). Plus normal factors such as nutrition and environmental conditions can have their effect on the size achieved by any individual specimen. Let's face it, a runt is a runt, even if carrying the Giant gene, the thing ain't magic. Topping all of this off is that it seems the Giants commonly grow at a slower rate than other types, and many of ours have taken two years to achieve full size and are still growing, albeit slowly.
   

• Mack Snow
  Here we have the second known codominant mutation in Leopard geckos, and perhaps the most exciting of all. Labeled after its originators, John and Amy Mack to eliminate confusion with a selectively bred line of Snows also available.
  Since the mode of inheritance of codominant mutations is so poorly understood by most Leopard Gecko keepers, I'll attempt to explain it here in some detail (again):
  
  With regard to the Mack Snow mutation and it's effect on appearance, Leopard Geckos can exists in three possible genetic states: Normal (no mutated alleles present), Mack Snow (one mutated allele present) and Mack Super Snow (two mutated alleles present).
  
  1) Normal specimens (no mutated alleles present), are of course, just that - completely normal in every way. They exhibit no characteristics of the Mack Snow mutation, nor can they be heterozygous for Mack Snow. In the above photo, a normal specimen is at top.
  
  2) Mack Snow specimens (one mutated allele present) can be immediately distinguished as hatchlings by their considerably lighter overall appearance. Sometimes these are also simply called 'Macks'. Strictly speaking, these are in fact heterozygous and typical rules of inheritance apply when breeding them - the only thing different here is that such heterozygous specimens can now be spotted visually, something that cannot be done with simple recessive mutations! In the above photo, a Mack Snow specimen is at bottom.
  
  3) Mack Super Snows (two mutated alleles present) show even more of these effects, appearing nearly pure white with what remains of the black spotting usually arranged into lengthwise stripes. Most interestingly, they also have startling solid black eyes! Hatchlings are so obviously different in appearance that there can be no possible confusion among them. They are uniquely unmarked an almost solid gray at hatching. These are in fact homozygous, and typical rules of inheritance apply when breeding them. In the above photo, a Mack Super Snow specimen is at center.
  
  Understand the mode of inheritance and the predicted outcomes of various crosses can greatly simplify sorting out the results. Perhaps the following will help:
  
  Normal x Normal yields all Normal offspring.
  Normal x Mack Snow yields half Normal, half Mack Snow offspring.
  Normal x Mack Super Snow yields all Mack Snow offspring.
  Mack Snow x Mack Snow yields 1/4 Normal, 1/2 Mack Snow, 1/4 Mack Super Snow offspring.
  Mack Snow x Mack Super Snow yields 1/2 Mack Snow, 1/2 Mack Super Snow offspring.
  Mack Super Snow x Mack Super Snow yields all Mack Super Snow offspring.
   

• Enigma
  Here we have the first known dominant mutation in Leopard geckos, and a very exciting mutation indeed! Discovered by Mark & Kim Bell, prodigious reptiles breeders indeed, and initially marketed and named by Kelli Hammack in 2005.
  
  Specimens exhibiting this trait develop spots and patches of coloration in unusual locations, yielding a "calico" appearance as adults. The specimen illustrated here is a juvenile and will develop more of this coloration as it matures. Between the unusual appearance and the unusual dominant mode of inheritance, the exact nature of these geckos was initially something of a mystery, or enigma, hence the name.
  
  Since the mode of inheritance of dominant mutations is new to most Leopard Gecko keepers, I'll attempt to explain it here in some detail.
  
  With regard to the Enigma mutation and it's effect on appearance, Leopard Geckos can exists in three possible genetic states: Normal (no mutated alleles present), Enigma (one mutated allele present) and Enigma (two mutated alleles present).
  
  1) Normal specimens (no mutated alleles present), are of course, just that - completely normal in every way. They exhibit no characteristics of the Enigma mutation, nor can they be heterozygous for Mack Snow. In the above photo, a normal specimen is at top.
  
  2) Enigma specimens (one mutated allele present) can be easily distinguished as hatchlings by their lighter overall appearance, and quickly develop the beginnings of the spots and blotches typical of adults. Strictly speaking, these are in fact heterozygous and typical rules of inheritance apply when breeding them - the only thing different here is that such heterozygous specimens can now be spotted visually, something that cannot be done with simple recessive mutations!
  
  3) Enigma specimens (two mutated alleles present) are suspected to be of identical appearance, as no obviously different specimens have appeared from breedings between two Enigmas thus far. As of this writing, it is unclear whether specimens proven homozygous for this trait exist as breeding trials will be required to identify them and clarify this issue.
  
  Understand the mode of inheritance and the predicted outcomes of various crosses can greatly simplify sorting out the results. Perhaps the following will help and is based on the presumption that Enigma specimens possessing two mutated alleles will not differ in appearance from those possessing a single mutated allele.:
  
  Normal x Normal yields all Normal offspring.
  Normal x Enigma (one mutated allele present) yields half Normal, half Enigma (one mutated allele present) offspring.
  Normal x Enigma (two mutated alleles present) yields all Enigma (one mutated allele present) offspring.
  Enigma (one mutated allele present) x Enigma (one mutated allele present)  yields 1/4 Normal, 1/2 Enigma (one mutated allele present), 1/4 Enigma (two mutated alleles present) offspring.
  Enigma (one mutated allele present) x Enigma (two mutated alleles present) yields 1/2 Enigma (one mutated allele present), 1/2 Enigma (two mutated alleles present) offspring.
  Enigma (two mutated alleles present) x Enigma (two mutated alleles present) yields all Enigma (two mutated alleles present) offspring.
   

'Multiple Genetic Trait Leopard Geckos
All of the Leopard Gecko Morphs presented in this section are affected by two or more mutated alleles. Many have become common enough to have well-known trade names. Other trade names are fairly new, and will hopefully be used regularly enough to become established. Many multiple trait Leopard Geckos are simply called by the combination of traits involved. Examples of this are Giant Albino or Patternless Mack Snow, although there are of course dozens more! We won't bother listing all of these 'combination' names, since most are pretty self-explanatory, but we'll show most of the more well-known ones.

• Patternless Tremper Albino
  Double homozygous for Murphy Patternless and Tremper Albino.
  
  Interestingly, these have proven somewhat difficult to produce from scratch. Apparently, the Tremper Albino locus is situated fairly close to the Murphy Patternless locus and a slight tendency for trait linkage is expressed. Many breeders report approximately 1 in 50 Patternless Tremper Albino offspring are produced when working with double heterozygous breeders, rather than the anticipated 1 in 16!
  
  Note that the three different types of Patternless Albino have been given different names for a reason - they are NOT compatible when bred together, due to the three types of albinism used to create each.
   

• Patternless Las Vegas Albino
  Double homozygous for Murphy Patternless and Las Vegas Albino.
  
  Note that the three different types of Patternless Albino have been given different names for a reason - they are NOT compatible when bred together, due to the three types of albinism used to create each.
   

• Patternless Bell Albino
  Double homozygous for Murphy Patternless and Bell Albino.
  
  Note that the three different types of Patternless Albino have been given different names for a reason - they are NOT compatible when bred together, due to the three types of albinism used to create each.
   

• Blazing Blizzard (Tremper Albino)
  Double homozygous for Blizzard and Tremper Albino.
  
  Interestingly, these have proven rather difficult to produce from scratch. Apparently, the Tremper Albino locus is situated fairly close to the Blizzard locus and a strong tendency for trait linkage is expressed. Many breeders report approximately 1 in 200 Blazing Blizzard offspring are produced when working with double heterozygous breeders, rather than the anticipated 1 in 16!
  
  Note that the three different types of Blazing Blizzard have been given different names for a reason - they are NOT compatible when bred together, due to the three types of albinism used to create each.
   

• Blazing Blizzard (Las Vegas Albino)
  Double homozygous for Blizzard and Las Vegas Albino. To our knowledge, these were first produced in May, 2004 by Garrick DeMeyer. At this point they are extremely rare in captive collections. However, it is certain that various breeders are already working on them and they will appear in the trade soon. Hatchlings do not appear to be significantly different from the Blazing Blizzards created using the Tremper strain albinos, likely the result of the Blizzard trait overshadowing the more subtle effects of the various types of albinism.
  
  Note that the three different types of Blazing Blizzard have been given different names for a reason - they are NOT compatible when bred together, due to the three types of albinism used to create each.
   

• Blazing Blizzard (Bell Albino)
  Double homozygous for Blizzard and Bell Albino. As of this writing, these have not yet been produced, but it's a certainty that breeders are already hard at work on them!
  
  Note that the three different types of Blazing Blizzard have been given different names for a reason - they are NOT compatible when bred together, due to the three types of albinism used to create each.
   

• Big Mack
  Double heterozygous for Giant and Mack Snow. It's to be expected that specimens double-homozygous for both traits will also soon appear (as well as combinations), and are expected to wind up with the trade name of Super Big Mack or perhaps Super-Sized Big Mack?
   

• Banana
  Double homozygous for Blizzard and Murphy Patternless. Originally, this name was applied to several yellowish colored specimens of Blizzard Leopard Gecko, under the assumption that these specimens were examples of Patternless Blizzard. This was later proven incorrect. So now we are left with a quandary: Do we continue to label such yellowish examples of Blizzard with this name, or do we reserve it for the true Patternless Blizzard as it was originally intended? I vote for the latter.
  
  Note: While several keepers claim to have Patternless Blizzard specimens, to my knowledge there are no proven examples of this double homozygous morph in existence. Since it is suspected that these geckos may not be visually distinct from either the blizzard or the Patternless, suspected specimens would need to be bred to both types and the results recorded to prove their genotype without question. To date, nobody seems to have done this.