The lavender merle coat color in dogs is a striking and increasingly sought-after pattern, captivating with its unique appearance. This coloration results from genetic factors influencing pigment expression. Understanding the genetic foundation and potential health considerations associated with this specific coat type is important for both current and prospective dog owners.
Understanding Lavender Merle
Lavender merle is a diluted, softened version of the standard merle pattern, offering a distinctive visual appeal. It features irregular patches of pale, silvery-grey or a muted brownish-purple hue, set against an even lighter, often creamy or ash-toned background. This pattern creates a marbled effect, where the boundaries between the darker patches and the lighter base color can appear jagged or torn. Unlike blue or red merle, lavender merle achieves its unique coloration through further dilution of these base pigments.
The eyes of a lavender merle dog can also reflect this diluted pigmentation, often appearing blue, partially blue, or even heterochromatic. The nose and paw pads may also show mottled pink and black areas, highlighting the widespread effect of the genes responsible for this pattern. The overall impression is one of a soft, pastel-like appearance.
The Genetics of Merle Patterns
The merle pattern is primarily controlled by the merle (M) gene, which is inherited in an autosomal incomplete dominant manner. This gene causes random dilution of eumelanin, the dark pigment responsible for black and brown coloration, leading to areas of full color alongside lighter, diluted patches. A dog needs only one copy of the merle allele (Mm) to display the merle pattern.
For the coat to appear “lavender merle,” the dilution (d) gene must also be present. This gene, located on the D locus and involving the MLPH gene, is recessive, meaning a dog must inherit two copies of the dilute allele (dd) to express its effect. The dilution gene lightens both eumelanin and phaeomelanin (red pigment), transforming black to blue (grey) and brown to isabella (lilac/lavender). Therefore, a lavender merle dog is a merle dog whose underlying black or brown pigment has been further lightened by the presence of two copies of the dilution gene, resulting in the characteristic muted, purplish-grey tones.
Breeds with Lavender Merle
The lavender merle coat color can emerge in breeds that carry both the merle gene and the recessive dilution gene. While merle patterns are well-established in many breeds, the specific combination that creates lavender is less common. Breeds recognized for carrying the merle gene include the Australian Shepherd, Border Collie, Shetland Sheepdog, Dachshund, Great Dane, Collie, and Chihuahua.
The dilution gene, necessary to achieve the lavender shade, is also present in various breeds. When these two genetic components combine, the unique lavender merle coloration can appear. Some breeds where a lilac or lavender merle has been noted include the Pomeranian and Old English Bulldog, often through selective breeding efforts.
Health Implications of Merle
The merle gene, particularly when inherited in two copies (homozygous merle or “double merle”), carries significant health implications. Dogs with two merle alleles (MM genotype) often exhibit a much lighter, sometimes almost entirely white, coat due to extensive pigment suppression. This extreme lack of pigmentation is linked to severe auditory and ocular defects.
Common health issues in double merle dogs include congenital deafness, which can affect one or both ears. Ocular abnormalities are prevalent, such as microphthalmia, a condition where the eyes are abnormally small and can be non-functional. Other eye problems may include abnormal pupils, missing reflective layers in the eye, and various forms of vision impairment, sometimes leading to complete blindness. Beyond sensory issues, double merle dogs may also experience increased sensitivity to sunlight and a higher susceptibility to skin cancer due to their reduced pigmentation.
Responsible Breeding Considerations
Responsible breeding practices are important when dealing with the merle gene, especially when diluted patterns like lavender merle are desired. The primary concern is to prevent the breeding of two merle-patterned dogs together, as this carries a high risk of producing double merle offspring with severe health problems. Such pairings increase the probability of puppies inheriting two copies of the merle gene, leading to the aforementioned auditory and ocular defects.
Genetic testing is a valuable tool for breeders to identify whether a dog carries the merle gene, including cryptic merles that may not visibly display the pattern. By knowing the genetic makeup of breeding animals, breeders can make informed decisions to avoid dangerous merle-to-merle matings. Prioritizing the health and welfare of the dogs over purely aesthetic traits is a fundamental aspect of ethical breeding, ensuring that unique coat colors like lavender merle are produced without compromising the well-being of future generations.