Preface

"The Incredible Story of Merle" - it seems somewhat of a fanciful subtitle to give a book that is about such a complicated genetic topic. Some might think that a subtitle including wording such as "SINE oligo(dT)" , "Poly-A tail" or "Retrotransposon Insertion" would be more appropriate given the subject matter but the history behind the findings and discovery of Merle's many phenotypes, especially within the past couple of years has been nothing short of incredible.

The story's plot - the sequence of events; all the characters that have played a part and how they are interwoven are incredible. If one person was missing from the story then the results we now see would not have been possible.

Of course the first person in our story is Dr. LA Clark, who identified the Merle SINE insertion in 2006. The test was then sold under a patent to IDEXX Laboratories and then resold to GenMark Laboratories. In 2009 GenMark stopped Merle testing altogether. The results were just not making sense with many dogs expressing no Merle pattern at all testing as M/M. The results were thought by many to be "flawed". Testing and the possibility of any further advancement came to a standstill.

In 2010 a lab in Germany, Biofocus, started Merle testing. At that time there were a growing number of Catahoulas in Europe and in 2011 our next important person, Dr. Helena Synková, enters the story's timeline. Helena's work with Dr. Beatrix Böckmann from Biofocus gave us the added clarification of the length of Ma (as well as Mc) and the general concept that the length of Merle's Poly-A tail has a decided impact on the coat pattern created. During the next few years this different length was noted on testing results but not officially named as an allele, so anyone looking at results had to have this knowledge of the base pair numbers.

In 2014 I enter the story - I was approached by a long-time Catahoula breeder to write a color genetics chapter for her book on the history of our breed. No color testing had been done in our breed as of that time and as I moved ahead with testing on all loci and researching, it became clear that the information could not be contained in a single chapter.

I decided to write my own book - "Catahoula Coat Color Genetics - Painting the Canvas".

As I researched Merle testing I contacted Biofocus regarding the length of Ma only to find that Dr. Beatrix Böckmann was no longer with the lab and Dr. Wagner, who was now the contact, had no idea what I was talking about regarding Ma and the various lengths of Merle! 
Yikes - a snag in the story!! I worked with Dr. Wagner for a few months and in May 2015 the Ma allele was officially added to the M Locus.

Further testing I did for my book was showing amazing results on the diluted expression that Ma could give to the coat in the absence of d/d, this was another great phenotype find and explained the coloring often referred to as "Maltese Merle". More testing confirmed examples of the shortening of base pairs from parent to offspring. I also included in the book the idea for the naming of base pair lengths between Mc and Ma as Mc+ and lengths between Ma and M as Ma+.

I released my book on Catahoula genetics in June, 2016 and in March 2017 our next important characters enter the story.

A representative from Vemodia Labs in the Czech Republic purchased the first release of my Catahoula book and expressed great interest in developing their Merle test for the different alleles.

In early fall 2016, RNDr. Tereza Jančušková, Ph.D. and MUDr. Soňa Peková, PhD. contacted Dr. Helena Synková and myself to arrange for the testing of 20 Catahoulas with already known Merle genotypes. The results of Vemodia's testing will be gone over in detail following in this book and include more incredible findings to add to the story - tri-allelic and quad-allelic Merle results, including information on "major" and "minor" alleles and the inclusion of Mh as well as Mc+ and Ma+, which you will see are important distinctions in lengths.

As more and more knowledge was acquired through the testing of many dogs from different breeds it became apparent that a formal research paper made available to the public was the next crucial step in helping breeders with the sometimes complicated intricacies involved with the M locus.

On May, 10, 2018 "Merle phenotypes in dogs - SILV SINE insertions from Mc to Mh" -
Authors - Mary Langevin, Helena Synkova, Sona Pekova and Tereza Jancuskova was submitted to PLOS ONE - a peer-reviewed open access scientific journal published by the Public Library of Science. On May, 22, 2018 the manuscript was released as a preprint on bioRxiv's website.
The manuscript was accepted on August 9, 2018 and published on September 20, 2018.
Langevin M, Synkova H, Jancuskova T, Pekova S (2018) Merle phenotypes in dogs - SILV SINE insertions from Mc to Mh. PLoS ONE 13(9): e0198536. https://doi.org/10.1371/journal.pone.0198536

On Sept, 22, 2018 the paper was published on PubMed's website - https://www.ncbi.nlm.nih.gov/pubmed/30235206

"The Incredible Story of Merle" spans 12 years - from knowing very little to the results you will see in this book.

As you go through the book I'm sure you will agree that it is truly an incredible story!