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Hyomelanistic Axolotls - a New Phenotype

**We expect to have hypomelanistic axolotls available for sale in March, 2022.  


What is hypomelanism?  The literal meaning of the term is used to describe an animal that produces less melanin (dark pigment) compared to normal or “wild-type”. Hypomelanistic axolotls are a magical and beautiful new phenotype still shrouded in mystery.  We are working on unlocking their secrets. 


In April 2021, Rainy Day Aquatics was the first breeder to recognize, identify, and describe a new phenotype of axolotl that we are calling “Hypomelanistic”. While it is suspected that this new phenotype has been present in the hobby for several years, it was not recognized as such until I was able to acquire and observe several individuals that seemed special based on photos sent to us by Roofus Aquatics.  The axolotls in the photos had first been described as gold albinos but had dark eyes. They were then thought to be a copper phenotype but were brilliant yellow in color. This piqued my interested and I purchased several of these, as well as what I originally thought was a leucistic sibling with unique yellow pigment patterning. After careful observation, and evaluation of the original clutch phenotype ratios, I determined that these beautiful brilliant yellow juveniles must be a new phenotype and started calling them hypomelanistic (“Hypo” for short). I also realized that the “leucistic” sibling was actually a hypomelanistic melanoid, not a leucistic at all.  


We have determined thus far that the genetic mutation that causes this form of hypomelanism is heritable and may possess a similar inheritance pattern as other phenotypes such as melanoid, axanthic, and copper.  We also know that this phenotype can be expressed alongside the mutations that cause the melanoid and copper phenotypes (ie we have been able to identify hypomelanistic melanoid and hypomelanistic copper individuals).  


Hypomelanistic individuals can be identified as having far less melanin than their wild-type counterparts.  It is yet to be determined if they have fewer actual melanocytes, but I predict the mutation is linked to less production of actual melanin within the pigment cells. This phenotype also appears to have an increased number of xanthophores (yellow pigment cells) as well as iridophores (reflective pigment cells). This is what causes their bright yellow-gold base coloration, with large clusters of sparkles. 


This project is particularly exciting because we have not seen a new color mutation in the USA since the first coppers were imported for the pet trade in 2011.  We are working with a select few quality/ethical breeders to determine the inheritance pattern and other identifying features of this new mutation.  Eventually, researchers will be able to identify the exact genetic mutation. 

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