Merle Gene Origins:

 

This study was conducted on the merle gene that was done at Texas A & M, published in the National Academy of Science (PNAS), a highly respected scientific journal. The PNAS paper is entitled: Retrotransposon insertion in SILV is responsible for Merle patterning of the domestic dog. L.A. Clark,J.M.Wahl,C.A. Rees, and K.E Murphy. 2006 January 31; 103(5): 1376-1381

 

This study validated a scientific study of six different breeds with a merle mutation. The study found the gene to be exactly the same in all the six breeds.  This study concluded that the merle mutation predates all dogs and is behind all breeds—quite possibly going back to their wolf ancestors!

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Below is some of the readings from this study:

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"The Dog as a Model"

The domestic dog (Canis familiaris) has served as a focal point of scientific curiosity for ages. Originating in East Asia, domestic dogs diverged exclusively from the gray wolf approximately 40,000-15,000 years ago, according to mtDNA evidence (Vila et al., 1997; Leonard et al., 2002; Savolainen et al., 2002). Alternatively, archeological evidence suggests a later domestication event, around 14,000-9,000 years ago (Leonard et al., 2002; Savolainen et al., 2002). To date, there are over 1000 regional varieties and recognized breeds of dog world-wide, the majority of which were created in the past 250 years (Ostrander and Giniger, 1997; Neff and Rine, 2006). This rapid breed differentiation was accomplished using selective breeding practices, often from a very small number of founders (Ostrander and Kruglyak, 2000). The desire to breed dogs with specific traits led to a species that is unrivaled among mammals in diversity. Dog breeds differ in size, coat color and texture, craniofacial structure, body conformation, and behavior. Interestingly, the reproductive isolation of dog breeds has created relatively closed gene pools that can be studied as isolated populations (Patterson, 2000; Parker et al., 2004).

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Based upon this significant research, the Merle gene mutation was present before breeds emerged. This would include the Cavalier King Charlie Spaniel.

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Chocolate Cavaliers:

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We do not have a Chocolate Cavalier. Prior to 1973, Chocolate was a recognized King Charles Cavalier Spaniel color. They are very rare due to chocolate being a recessive gene. Chocolate and Merle are two colors that can show up through gene structure in cavaliers.

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The Chocolate Cavalier King Charlie Spaniel origins. The biggest problem the breed has is locating the extremely rare Chocolate gene. To the best of my knowledge there are only two known originating Chocolate King Charles Cavalier Spaniel bloodlines in the world! The fact is there an almost extinct coat color. What is the Chocolate King Charles Cavalier Spaniel? The Chocolate King Charles Cavalier Spaniel is a Cavalier carrying the recessive b locus (brown) gene! However, again there are only two known originating Chocolate King Charles Cavalier Spaniel bloodlines in the world! 

 

Thankfully with modern science there is a B locus DNA test that can be done to determine if a particular King Charles Cavalier Spaniel carries the recessive Bb or bb gene.  

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Prior to 1973, “All colors were recognized”. It was only in 1973 that the Breed Standard was changed to disallow for showing the whole color’s Blacks, Black & Whites, and the Chocolates. The Chocolate gene expresses itself as Chocolate Tan, Chocolate Tri, Chocolate Ruby, or Chocolate Blenheim. In both Chocolate Ruby and Chocolate Blenheim you can only visually see the brown foot pads, eye rims and nose. The eye color is also diluted to green blue! The b variant affects only eumelanin pigmented areas (Black) and not phaeomelanin (Red) pigmented areas.

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