How does the dilute gene cause Colour Dilution Alopecia? Colour Dilution Alopecia (CDA) is caused by a recessive genetic variant of the melanophilin (MLPH) gene, commonly known as the dilute gene. When a dog inherits two copies of this recessive variant (the homozygous d/d genotype), it alters the normal formation and storage of pigment in […]
Understanding the d Allele’s Role in Alopecia
What is the relationship between the d allele and alopecia? The d allele is a recessive variant of the dilute (MLPH) gene, and inheriting two copies of it (the homozygous d/d genotype) is the underlying cause of Colour Dilution Alopecia (CDA). Here is how the d allele and alopecia are related: • The Mechanism of […]
Understanding Cryptic vs Classic Merle Dogs
How do cryptic merles differ from classic merle dogs? The difference between cryptic merles and classic merle dogs lies in the length of the genetic insertion within the SILV pigment gene and how that length affects the dog’s physical appearance. • Cryptic Merles: These dogs have a shorter genetic insertion, measuring 25 to 44 base […]
Understanding Embryonic Death in Harlequin Great Danes
What causes embryonic death in Harlequin Great Danes? Embryonic death in Harlequin Great Danes is caused by inheriting two copies of the Harlequin gene, resulting in a homozygous (HH) genotype. The Harlequin gene acts as an embryonic lethal gene when inherited in this double form. When an embryo possesses the HH genotype, it fails to […]
Breeding Dogs: The Hidden Harlequin Gene
Can a dog carry Harlequin without showing it? Yes, a dog can carry the Harlequin gene without visibly showing it. This occurs when a dog inherits the Harlequin gene but does not inherit the Merle gene. Because the Harlequin gene acts specifically as a modifier to the Merle pattern, it requires the presence of the […]
Understanding the Lethal Harlequin Gene in Dogs
What is the lethal effect of the Harlequin gene? The Harlequin gene is embryonic-lethal when a dog inherits two copies of it. If a puppy inherits this homozygous HH genotype, the mutation causes embryonic death very early during pregnancy, meaning the embryo fails to form entirely and is instead reabsorbed into the womb. Because this […]
Impact of DNA Testing on Great Dane Color Standards
How has DNA testing changed the Great Dane color standards? DNA testing has provided definitive answers about the recessive genes dogs carry, fundamentally changing how Great Dane breeders approach coat color and breeding standards. This technology has shifted the Great Dane community away from pedigree-based guesswork and led to several major changes in breed standards: […]
Understanding Double Merle Dogs: Genetics and Health Risks
Explain the health risks and genetics behind Double Merle dogs. The Genetics Behind Double Merle Dogs The Merle coat pattern is caused by an incomplete dominant gene. A “Double Merle” dog is one that has inherited two copies of the Merle gene, resulting in a homozygous (MM) genotype. This typically happens when two merle or […]
Understanding Merle and Harlequin Gene Interaction in Great Danes
How do the Merle and Harlequin genes interact in Great Danes? The Merle and Harlequin genes interact closely to produce the unique Harlequin coat pattern in Great Danes. The Harlequin gene (located on the H locus) acts as a dominant modifier of the Merle gene (located on the M locus). Here is how these two […]
The Risks of Double Merle Breeding in Great Danes
Great Dane Genetics and Coat Color Standards Merle and Harlequin Interaction The merle gene (SILV/PMEL17, M locus) creates a dilute gray background with dark spots (incomplete dominant). The harlequin gene (H locus) acts as a modifier, turning the gray background to pure white. Harlequin cannot express without merle (M). Double Merle Risks Homozygous merle (MM), […]