Harlequin (H Locus) Great Dane Type

General Information: The H Locus (H) Harlequin locus in Great Danes produces a striking coat pattern characterized by irregular dark patches on a white background. This pattern is achieved through the interaction of the harlequin gene with the merle gene, where the harlequin gene modifies the typical merle pattern to enhance contrast and patch size. Only dogs that carry at least one merle gene can express the harlequin pattern. Physically, harlequin Great Danes display this unique coloration from birth, and it does not affect their general health aside from the coat appearance. However, breeding considerations are crucial due to the potential lethality of inheriting two copies of the harlequin gene, which can lead to embryonic death.

Gene / Testing Information: Genetic testing for the H-Locus (H) Harlequin trait in Great Danes focuses on the PSMB7 gene to determine the presence of the harlequin gene variant. This trait is inherited in an autosomal dominant manner, meaning a single copy of the mutated gene (H) is sufficient to produce the harlequin pattern. Each puppy from a harlequin parent has a 50% chance of inheriting the H gene. However, breeding two harlequin Great Danes is generally discouraged because puppies inheriting double copies of the harlequin gene (H/H) are thought to be non-viable and result in embryonic lethality, leading to smaller litters or unsuccessful pregnancies. For effective breeding practices, it is recommended to pair harlequin Great Danes (H/n) with non-harlequin (n/n) partners to prevent the risk of producing non-viable embryos and to ensure the continuation of the harlequin pattern without health risks to the puppies. This genetic testing not only assists in confirming the presence of the H gene but also helps in making informed breeding decisions to maintain the health and viability of the breed.