Great Dane coat colors are complicated because there are several color genes that affect the Great Dane's color. Some of these genes are dominant and some recessive, what this practically means is that if Great Danes of random colors are bred to each other, you cannot accurately predict the colors of the offspring, too many possibilities exist.

Before color genetic testing was available, Dane breeders had developed and practiced breeding practices that allowed them to consistently reproduce certain Great Dane colors, the colors that are currently recognized to be shown. Color genes were hypothesized by careful observation of Great Dane breeding practices and in the last decade, researchers have identified several of the Great Dane color genes.  

Various people have put together charts and drawings and made up names for all the various possible Great Dane color combinations, speculating that there are at least 20-30 or more different possible colors. If Great Danes from different color families are bred together, because of the number of colors possible, the breeder loses the ability of accurately predicting the possible colors. What sense does it make if a litter of 8 puppies has a 20% chance of having Fawn puppies, a 15% chance of having Merle, a 10% chance of being Black, a 10% chance of being Mantle, a 10% chance of being Fawntle, a 8% chance of being Brindle, a 12% chance of being Blue, a 15% chance of having Blue Mantles. Breeding dogs with lots of different color genes means that you lose the ability to accurately predict what colors will be produced.

People have thought about what would happen if all the Great Danes were bred without regard to color. Because the Black gene is dominant in most cases, it is thought that eventually most Danes would become some variation of Black. In order to get other colors, breeders would have to do what they have already done, start breeding only specific colors to specific colors to start separating out the color genes again so they can accurately predict what colors they will get with breedings.

If breeders have to start over and focus on color predominantly, they will have to place color as the most important aspect in breeding decisions, color above healthy structure and soundness, as well as breed type, temperament and longevity. This is re-inventing the wheel, this work has already been done by breeders 100 years ago and has allowed good breeders of Great Danes to now focus on structure, soundness, temperament, etc. Breeders today, using color testing and following the color breeding recommendations of the Great Dane Club of America, can breed their Great Danes and know what colors will be produced.