I am Mary Langevin - Author of "Merle - SINE Insertion from Mc - Mh - The Incredible Story of Merle".
The book is based on our published research paper  - Merle phenotypes in dogs - SILV SINE insertions from Mc to Mh
Langevin M, Synkova H, Jancuskova T, Pekova S (2018) PLoS ONE 13(9): e0198536 - "langevin et al"
https://doi.org/10.1371/journal.pone.0198536     Published: September 20, 2018

This petition is to request that all labs who are offering Merle testing update their website information especially in regards to the terminology of "Cryptic Merle", which has been used for decades to mean a dog who is a “hidden Merle”. The word cryptic is often used in conjunction with words such as “hidden”, “masked”, “ghost” and “phantom”. All the same descriptive words with the same meaning - a dog who was assumed by phenotype to be non-Merle and then bred as a Merle producing visibly Merle patterned offspring.
The use of the word “cryptic” in this sense has been used only as a general “descriptive” word and not in a true “genetic” manner. Used to describe something we could not understand as we did not yet have the technology available to us in order to discern the precise lengths of Merle’s poly-A tail.
Note: in some breeds cryptic is also used to describe a dog who is Minimal Merle.

"Cryptic Merle" now genetically refers to the "Mc allele on the M locus - 200 - 230 base pairs". Mc will express and breed the same as non-Merle and can very safely be bred to a visible Merle mate. Due to websites who use the old catch-all, convoluted and non-genetic meaning of the term, breeders are neutering/spaying dogs tested as Mc and removing them from breeding programs due to the fear that Mc means “hidden”, “ghost” and “phantom” Merle. That their Mc dog could possibly breed the same as a Merle and may produce impaired offspring. If this trend continues genetic diversity could be greatly impacted. The following article I wrote for the Australian Shepherd Club of America goes over this in detail - 
Unraveling the Mysteries of Merle.

This webpage explains in detail the Mc allele - 200 - 230 bp
Defining - Mc - Cryptic Merle

Please sign this petition asking labs and breed clubs to update their Merle information to include the most current genetic information.