INTRODUCTION- My Journey into this project. 

From the beginning of my breeding journey, Soft Scale Crested geckos have been my passion. I was attracted to the expressed gene as a Super (homozygous). The vibrant colors, matte-like appearance, and incredible structure these animals possessed was what excited me about breeding. I focused on creating the best version of the Crested Gecko using this specific genetic trait and dove head first into investing in as many Super Soft Scale Crested geckos as I could get my hands on. As I continued working with these animals and studying them more closely, I began recognizing a pattern among offspring that started to raise questions as to what exactly was going on in my collection. Similarly, Daniel Foley had been seeing trends and was asking me the same questions. Not only were we questioning ourselves for validity in our projects, but others were reaching out with the same question time after time…

 

 How do I know if I have a “Soft Scale” versus a “Normal” Crested Gecko…

 

Yet, for this common question, we did not have a definitive answer. How can we be so passionate about a specific genetic yet need straightforward answers to some of these most pressing questions? As breeders and entrepreneurs both with backgrounds in science, this was not going to cut it. In a search to answer these questions, Daniel Foley and I set out to determine how to identify a Soft Scale mutant gene and the visual markers denotining it.

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~Nicholetta Donaldson~

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Proposed Explanation for Soft Scale in Correlophus Ciliatus (Crested Gecko) 

Nicholetta Donaldson & Daniel Foley

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SOFT SCALE CRESTED GECKOS BY CURRENT DEFINITION

The Soft Scale Crested Gecko genetic, by current definition, has left room for broad interpretations as to how this gene expresses itself in both the homozygous and heterozygous forms. The definitions below are cited and are available in more detail on the website links.

 

Anthony Caponetto, the founder of the gene (Anthony Caponetto Reptiles):

“The Super form of the Soft Scale gene, you see distinct spacing between the scales, and the scales appear smaller” 

“Upon examining some professional macro photographs, and looking at some of the more extreme examples of Super Soft Scales under a photographer's loupe, it appears these geckos exhibit fewer bumps or "scales" on their skin, leaving more space between”

“In short, we have an incomplete dominant (or "codominant" as it's called in the reptile world)

mutation that one could argue is a recessive because the Soft Scale is so subtle in single-gene form.” 

Citation: Individual Crested Geckos :: Soft scales & Super Softs. (n.d.). https://acreptiles.com/new_store/index.php?dispatch=categories.view&category_id=16

 

In 2021, in an Instagram post by LM Reptiles, the gene was “confirmed as a co-dom trait”, saying that “triangle microscales (referred to as secondary scales in this article), are reduced, and the space between them and the large scales (referred to primary scales in this article) is beginning to widen”. The post also notes that “the colors that received the biggest benefit were black, red, and lavender based animals, and the orange and tangerine harlequins” Furthermore, in Super Soft Scales “The microscales are almost no longer present and there is a large gap between the larger scales and large scales are more uniform”, and “the trait also produces silver eye colored animals and in the super form some animals have a dark ring on the outer edge of the eye”. 

 

And finally, the current definition on the LM Reptiles website (Foundation Genetics) states:

“This is purely a physical trait, which causes a color change due to how light reflects back. This is due to the physical changes of the chromatophore. In simple terms this gene changes the structure of the scales causing them to reflect different colors than what the animal would normally display. This gives the gecko a soft matte look to the scalation and color. The most affected colors are bases like citrus, and orange causing them to pop with a soft matte and often more intense color. Blacks are deeper, orange hues are matte, and tangerine animals produce a pinkish color that looks like soft serve ice cream. Yellow and red are a bit more difficult to see unless they are super soft. The lineage of this gene also seems to come from smooth animals with cleaner colors and less dramatic tigering. Originally identified in ACR’s collection this gene has already propagated in the community. It is best to breed out supers if you suspect you have one.”

Trait details:

CATEGORY: Structural

GENOTYPE: S3

PHENOTYPE: Incomplete dominant

Allelic with: none known

Citation : FG-PT2.1 » LIL MONSTERS Reptiles. (2023, August 7). LIL MONSTERS Reptiles.

https://lmreptiles.com/fg-pt2-1/#softscale

 

DISCUSSION

To begin the search for an answer as to what truly makes a "Soft Scale'' different from a

“Normal” (Wild type) crested gecko, the current definitions above were closely analyzed to conduct this study.

To reiterate:

-Anthony Caponetto states “in the Super form of the Soft Scale gene, you see distinct spacing between the scales, and the scales appear smaller” and that the gene is “incomplete, dominant”, or codominant in the reptile world”.

-When the gene was “confirmed” on Instagram in 2021 as a “co-dom trait” the post stated similarly that “there is a large gap between the larger scales”. It also mentions a color enhancement to "black, red and lavender based animals, as well as orange and tangerine harlequins",  a silver eye color, a “dark ring around the edge of the eye”and a “velvet soft feel”.

-Currently, the Foundations Genetics definition does not mention eye color changes, dark rings around the eye, or velvet soft feel, but states that “the lineage of this gene seems to come from smooth animals with cleaner colors and less dramatic tigering”, and the most affected colors are “bases like citrus and orange”, while “yellow and red were a bit more difficult to see, unless they are super soft”. It goes on to state that “it is best to breed out supers if you suspect you have one”. It lists the genetic as incomplete dominant.

 

It is generally agreed upon above that the genetic is incomplete dominant, and that there is a wider spacing between the scales. Also note that the current descriptions are vague when it comes to identifying the heterozygous form. By definition, in an incomplete dominant gene mutation, the phenotype (the look of ) the heterozygous gene should visually express itself differently than a normal (Wild Type). 

 

IDENTIFYING THE HOMOZYGOUS FORM

With the observable traits listed above gathered, the next step was to identify the Super form in our collections.The initial study was conducted with a professional Dinolite handheld microscope https://www.dinolite.us/products/usb-microscopes/usb-edge-plus/am8917mzt/. The microscope was used to identify the Super Soft Scales in Nicholetta Donaldson and Daniel Foley’s collections.  The possible Super Soft Scales were identified using a 50x magnification in which a notable scale spacing consistent with the super soft scale phenotypic descriptions above was observed. Below are examples at 64x magnification.

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 *Note* This was the most challenging part of the project for both of us. Having both collected and bred for this specific genetic avidly for several years, we were perplexed by our findings. Animals we expected to be Super Soft appeared “normal”, and pairings specifically set up to produce Super Soft offspring had not. Although we felt defeated, we were determined to have a clear definition and/or identifier for BOTH the homozygous AND heterozygous forms. 

 

Next, the now confirmed Super Soft Scales were analyzed further. These Supers were initially identified as specimens with abutting scales at the center of the widest part of the head, not touching one another under a 50x magnification. The goal after seeing this initial scale spacing was to get a closer look in hopes of determining a cause or any extra information about the notable scales. In the following scans, the magnification was increased. There was notably more information at this magnification, and it was realized that there is more than just spacing between the scales. This phenomenon began to be noticeable at 175x + magnification. There is an apparent splitting or proliferation of what are extra scales between them.

 

At this point, it was deemed that the large scales recognized by the naked eye were to be called “primary scales'' and the new ones in the “scale space” as “secondary scales.” (They are referred to as such in this article as we advance and shown in the figures below) This pattern is consistent throughout all geckos that initially showed spacing in the 50x magnification. The secondary scale proliferation/splitting is present on the majority of the head and dorsal of all Super Soft Scale subjects.

 

After this initial phase the study was conducted and conclusive; multiple offspring holdbacks aided our further determinations and data mapping. The offspring from the proven Super x Super

pairings (27 in total over 20 grams) inherited the scale spacing with the secondary scale

proliferation 100% of the time. The scale spacing and proliferation/splitting now proved to be a

distinct physical characteristic to recognize the Super Soft Scale from the Wild Type. This

information guided the continuation of studies on what to look for in an intermediary heterozygous form. Diagrams depicting the findings follow:

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IDENTIFYING HETEROZYGOUS FORM

The offspring from the proven Supers (homozygous) bred to a Wild Type (normal) were looked at next. By genetic inheritance, all are the visual heterozygous mutation Soft Scale. Previously, attributes such as base color, eye color, and physical “feel” had been analyzed in these confirmed Soft Scale specimens. The initial analysis of these attributes took some time. The results yielded numerous discrepancies as it was subjective information that offered an inconsistent result. Some characteristics were hard to quantify, and further (according to the current Foundations Genetics definition) “the lineage of this gene seems to come from smooth animals with cleaner colors and less dramatic tigering” there is a question as to how much effect observed is bloodlines vs. how much is due to the the Soft Scale gene mutation. In short, nothing correlating the scale spacing in the homozygous Super Soft Scale to that of the base color, eye color, or physical “feel” of the heterozygous was found. 

 

The study now solely was focused back on the scale spacing that was proven to be consistent 100% of the time with inheritability. If the Soft Scale gene mutation is consistent with incomplete dominance, the phenotype (look of) the heterozygous should show a degree of spacing in the scales to a lesser degree than that of the homozygous. The degree of spacing in the heterozygous should also be distinguishably different from that of the Wild Type (normal).

 

 In the initial look at the heterozygous (Soft Scale) subjects there was no evidence of extra spacing nor secondary scale proliferation/splitting. The look under the microscope showed no variation in scalation than that of a Wild Type (normal). With this information at hand a few measurement tests were developed to give more conclusive data. Three quantitative data analyses were run, including the diameter of the scale from each type, measurement of the spacing between scales on an average, and the total number of scales in a standard area. 

 

Summary of our methods are below;

● Dino Lite Edge Plus (AM897MZT) Handheld Microscope with video.

● Gecko subject's number were maximized while attempting to minimize weight range, which

is noted below each figure

● All measurement photos were taken on top of the head between the widest crests.

● All measurement photos were taken at 64x-65x magnification for spacing analysis.

● All measurements were run on a multi-scale average with the same amount of scales

measured in each.

● All measurements were conducted in a manner to eliminate bias

● Measurements were taken using Adobe Acrobat Measure Tool and adjusted for minor

fluctuations in magnification readings seen in images below.

● There were no geckos expressing the Phantom or Lilly White genetic in this study.

 

Note* Scales measured outside of the head and dorsal are invalid areas to look at when determining spacing according to the methods of this article. All Crested Geckos have a varying degree of spacing between scales in these areas.

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Figure 3. Measurements of each genetic variation were taken across the widest part of their

primary scales from the central location at the widest part of their head. For this figure, sixteen

animals weighing 39g-45g from each genetic variation were photographed, and each photograph

split into four quadrants. Measurements were then taken between the center of a central scale and

all of its abutting scales within each quadrant. Averages for each representative photos are shown

below its photograph with overall averages from the three genetic variations being: (Wild

Type=32.704/64=.511mm/avg, Soft Scale (Heterozygous)=32.832/64=.513, Super Soft (Homozygous)= 38.74/64 = .605). These averages represent roughly an 18% increase in scale spacing among Soft Scale and/or Wild Type specimens.

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Figure 3&4 summary: In all 39 heterozygous subjects, there was no evidence of extra spacing nor secondary scale proliferation/splitting of the heterozygous form. The size of the scales in the heterozygous and wild type(normal) also show no difference. In both magnifications for all tests, the Soft Scale and wild type(normal) were seemingly identical. 

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CONCLUSION

After all measurements were complete and comparisons recorded, it is observed that the phenotype (look of) the heterozygous (Soft Scale) does not visually support incomplete dominance genetics. Instead, from this study's observations, the Wild Type (Normal) acts dominant to the heterozygous (Soft Scale), meaning it is likely to be a recessive gene. The homozygous (Super Soft Scale) displays a wider scale spacing with scale proliferation within and a smaller scale diameter, which is not observed in the heterozygous (Soft Scale) form. The results show NO notable difference between the heterozygous (Soft Scale) specimens and the Wild Type (Normal) specimens. The average spacing and scale amount showed less than .3% variability between the two and trended opposite to the homozygous(Super Soft Scale) results, which averaged an 18% larger scale spacing than the Wild Type (normal). Similarly, scale diameter results varied by only 1% between Wild type(normal) and heterozygous (Soft scale) specimens. In comparison, the Homozygous (Super Soft Scale) form was 6.8% smaller than Wild Type(normal), and 7.9% smaller than those heterozygous (Soft Scale) Specimens examined. An argument could be made that the heterozygous (Soft Scale)could display an altered scale depth, which is not covered in the measurements above. While this is unlikely, some photographs were analyzed, and this is not the case. It is also important to note that the possible phenotype (look and feel) associated with the heterozygous (Soft Scale) is likely due to other traits and polygenic properties associated with line breeding, and further, the noted color hues and feel of the heterozygous(Soft Scale) animals are not a means to identify the gene. There are no known physical attributes of the visual heterozygous (Soft Scale) to that of the Wild Type (Normal) with the scale spacing and proliferation/splitting seen in the homozygous(Super Soft Scale) form. 

 

Below is the proposed definition written by the authors of this article. The proposed changes will address the confusion currently in place for this genetic.The accuracy of this genotype makeup is imperative for advancing further genetic research for the Correlophus Ciliatus(Crested Gecko). 

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The Soft Scale (currently known as Super Soft Scale) Crested Gecko Genotype is a Recessive mutation in which the "primary scales" are spaced farther apart than the Wild Type (Normal) Crested Gecko. The scale spacing in the full expression(homozygous) of this gene is accompanied by the proliferation or "splitting" of the secondary scales that reside between the primary scales on the gecko's head and dorsal. Scales also show a smaller diameter as compared to their wild-type counterparts. The phenotype (the look of) of the Heterozygous gene carrier shows no visual difference from that of the Wild Type (Normal). Soft Scale is an inheritable mutant gene that results in a change to the gecko's physical appearance that enhances both color and pattern when compared to the Wild Type(Normal). The degree to which you can see this depends upon the corresponding lines crossbred into the gecko.

 

Genotype: Recessive

Soft Scale: Homozygous form

Wild Type (Normal-No Soft Scale Present)

 

Soft Scale x Soft scale = 100% Soft Scale

Soft Scale x  Het Soft Scale = 50% Soft Scale + 50% Het Soft Scale

Soft Scale x Wild Type = 100% Het Soft Scale

Het Soft Scale x Het Soft Scale = 25% Soft Scale + 50% Het Soft Scale + 25% Wild Type

Wild Type x Het Soft Scale = 50% Wild Type + 50% Het Soft Scale

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FURTHER INFORMATION-CLOSING STATEMENT

I am very excited for the future of the Soft Scale gene regarding our findings. The proper identification of the genotype will bring longevity and validity to all projects including Soft Scale animals. The best animals are still yet to be seen. Both Daniel Foley and myself are working hard to continue to this project now focusing on how the Soft Scale gene affects the Lilly White and Phantom gene mutations. Our goal is to continue to grow our knowledge and continue to produce the most incredible animals possible. This information with more pictures and diagrams will be available in E-book form January 1st 2024. Thank you for your continued love and support! 

~Nicholetta~