Foundation Genetics - Finding Phantom

Finding Phantom

Updated: 2/13/24, v1.1

Fixed a typo, and swapped non-mendelian for mendelian.

There are some clues, when looking at a crested gecko, to determine if it carries the Phantom trait. The simplest clues come from understanding other terms we use (see rule 1), which are descriptors, rather than actual traits. Actual traits have been capitalized in this reference, in order to differentiate them from descriptors.

RULE 1:

Bi-color and patternless animals have the Phantom trait. Therefore, any bi-color or patternless animals are Phantom.

RULE 2:

If a yellow-based animal has melanin blended in it, making it buckskin, cream or tan, it has Phantom. A clean yellow base is Hypomelanistic and does not blend with a Black Base. If it appears blended it has to come from another melanin-producing trait. That trait is Phantom.

RULE 3:

If you are looking at a Pinstripe, with some White Pattern on the raised scalation, the White pattern will fade to base color as it goes from the base of the tail to the head when Phantom is present. The White Pattern loses its dominance to Phantom.

Rule 4:

When you see a Pinstriped animal that has lower lateral pattern, but no upper lateral pattern, yet has Tiger pattern and a darker color in the center of the dorsum, rather than a high white, it is a lower dominance Phantom. A higher dominance Pinstripe is showing it's strength in this case. The Pinstripe has partially overcome rule 3 to a good degree, but the largest portion of the head will still remain darker. The hobby has stacked Pinstripe for many generations, so this phenotype is a product of long-term breeding practices.

Phantom has a range of dominance. Sometimes we mention them being heterozygous or homozygous as it is recessive. Heterozygous animals can potentially show indicators that we feel are Het for the trait and homozygous animals have different expression levels within the hobby due to other traits that are present. This teaching method helps hobbyists take the first step in understanding that Phantom can present itself in more than one way. We can now refer to the upper level of expression as more dominant, and the lower level as less dominant, when describing the Phantom trait in crested geckos.

 

The greatest issue, in defining Phantom, is the difference of opinion based on human descriptors. These descriptors have broken a single trait into multiple named phenotypes. These phenotypes have been misleading the hobby into thinking they are separate traits. The highly polymorphic nature of crested geckos lends itself to alternative phenotypes or forms. Finding the connections takes some due diligence.

 

Phantom acts recessively and falls under Mendelian genetics. Thinking it is non-Mendelian has caused some hobbyists to take our presented information out of context. Spreading this, and other false or limited/corrupt data lends itself to dividing us from one another. It also skews theories that end up off-base and biased. With Phantom, many animals are not tracked properly. It can be from not identifying Phantom properly and/or using simple general lineage that is not your own or not properly founded. When we use lineage from geckos that are from other breeders, or from our geckos bred to other breeder's animals, it is not reliable until the animals are test bred and genetically proven for specific heritable traits. This can take several generations provided you actually understand the traits.

 

This article is meant to help new and seasoned breeders alike. It is a general rule guide when looking at geckos at shows or online, so you may try to avoid or look for potential Phantom and Het Phantom animals, depending on your breeding plans.

Various Phantoms that can be found in the Hobby.

  • Tom Favazza - @Geckological
  • Anthony Vasquez - @lm.reptiles – www.lmreptiles.com