Colore del mantello Merle

The M-locus determines the merle pattern in dogs and consists of several variants (different SINE lengths) that influence how strongly the pattern is expressed. Dogs with the N/N (wild-type) variant do not carry the merle gene and show no merle pattern. Cryptic merle (Mc) dogs are genetically merle but usually show little to no visible merling, meaning they may easily be mistaken for non-merle dogs. A transitional form, known as cryptic merle+ (Mc+), may show very subtle merle markings.

Atypical merle (Ma) causes a slight dilution of the coat colour, while atypical merle+ (Ma+) results in stronger dilution and may appear more merle-like. Classic merle (M) produces a clearly visible merle pattern, often accompanied by blue or partially blue eyes. The strongest expression, harlequin merle (Mh), leads to extensive dilution with white patches and is associated with an increased risk of hearing and eye-related health issues.