Blue Merle Great Dane – Everything you Need to Know

What is a Blue Merle Great Dane?

A Blue Merle Great Dane is the combination of the Dominant Merle Gene and the recessive Blue Gene. The Blue gene is not common due to this in the Great Dane. Despite the Merle pattern coming from a dominant gene it is also not the most common pattern found on a Great Dane. This is due to Merles being unable to safely breed with other Merles. Which would guarantee the gene is passed on.

The Blue Gene is officially known as the Dilution Gene. When performing a DNA test this will show up a small d indicating it’s recessive. The Blue color can often be described as Gray and is the dilution of pigmentation in the coats color. Due to this being a recessive gene it requires both parents to pass a copy to produce Blue Puppies. This however does not mean that both parents need to be Blue but this does significantly increase the chances.

The Merle Gene itself whilst Dominant isn’t something breeders aim to produce. This is due to potential health issues around the Merle gene. Whilst a regular Merle dog does not have a noticeable increase it’s increased largely for Double Merles. The pattern itself is often described as mottled patches of fur. They appear often as smaller patches around the face and then larger on the body.

What is a Blue Merlequin?

A Blue Merlequin Great Dane refers to a Great Dane that has both the Merle Gene and the Harlequin Gene. These are both Dominant genes and only require one copy to be passed on. Due to this it is not difficult to breed for if targeted.

The Harlequin gene only ever presents itself when the Merle Gene is also present. The Harlequin has a similar pattern to that of a Dalmatian. When this is combined with the Blue coloring this leads to a Blue base coat and Dark Blue spots over their body.

When the Harlequin Gene is present without the Merle Gene it doesn’t show at all in the pattern. Therefore there can be a number of Great Danes which have the Harlequin Gene without anything visually to identify them. Unfortunately there can also be health issues attached to that of the Harlequin gene so it is important to understand your Great Danes genetics before breeding.

What’s the difference between a Merle and a Harlequin?

Whilst they are often spoke about together there are large differences between Merle and Harlequin genes. The Merle gene itself is a pattern that can be seen on the coat of a Great Dane while the Harlequin Gene isn’t visible without the Merle gene. It is unsurprising therefore that the Harlequin gene is often grouped up with Merle when it is spoken about.

Merle is a Dominant Gene and only requires one parent to pass a copy on to any offspring. It is incredibly important to not breed two Merles together due to this leading to significant health issues. The pattern itself is often described as patches of mottled fur. This usually displays itself as a darker color with smaller patches around the face and slightly larger on the body. No pattern is the same however and can vary wildly.

Harlequin is often a silent gene within Great Danes and it is not obvious when present. The gene itself leads to more established spots of darkened fur when combined with the Merle Gene. Similar to the Merle Gene, Harlequin is also Dominant meaning it only requires one copy to passed on from a parent. It unfortunately shares similarities relating to health issues also. You should never breed two Harlequin dogs together due to two copies of the gene being fatal. It is not known that any puppies containing two copies of this gene have ever made it past the embryotic stage.

Merle Health Issues

It is difficult to know if single Merle Great Danes have health issues although studies have indicated generally Merle dogs have a higher risk of health issues.

Some of the Health issues linked to the Merle gene are the following.

  • Deafness – There is an increased risk of deafness or hearing issues compared to a regular Great Dane
  • Blindness – Dilation of the pupils can be an issue which can lead to night blindness and in some cases complete blindness.
  • Further Eye Issues – There is also a risk of eyes being off centre, additional eyelids, missing tissue or in some cases being born without eyes.
  • Immune Deficiency – A high risk of a having a weakened immune system.

The above are highly likely to occur in Double Merle Great Danes with the majority being deaf.

Great Dane Health Issues

Great Danes like most dogs can suffer a range of health issues with many related to their large size. Below we outline some of the more common afflictions. These are in addition to the Merle Health Issues.

Hip Dysplasia 

This leads to a reduced range of movement in the hind legs along with a reluctance in jumping, running and climbing stairs. Ensuring they stay at a healthy weight and are fed a high quality diet will help delay the onset.

Gastric Dilation Volvulus (GDV)

This is largely associated with eating large meals rather than several smaller meals. Studies have shown that dogs which are fed one large meal a day are more likely to be afflicted. In addition it has been observed that foods high in oils such as sunflower or animal fat can be a contributing factor. Whilst this illness can be life threatening in the worst of cases there are additional ways to reduce the risk. Elevated feeding is recommended as a way to reduce this pressure in addition to several meals a day.


Great Danes can be prone to allergies like most other dog breeds. This will usually display in red/raw patches often around their paws. Also it can show through watery eyes, ear infections or sneezing. If you suspect allergy issues it is best to discuss with a vet around possible treatments.

Heart Disease 

Great Danes can be prone to Heart disease, the best way to reduce this risk is through breeding. It is important to find out the medical history of any puppies parents as this will be the best indicator of risk.