The color set is comprised of a single pair of "simple recessives." The puppy gets one from the "mom," one from the "dad" at conception. The black gene is the dominant gene, designated by a "B," and the red recessive is termed "b." Note that capital letters are used for the dominant gene, and small letters for the recessive. Simple recessive means that if you have even one dominant gene (B), that gene will determine the color. There is NO way to tell whether a black carries the recessive (Bb) by looking at the dog. In other words, you MUST have a bb combination (two recessives) to have the red (or fawn) color.
Now, dilution (my favorite subject!). The dilution genes are also a set of simple recessive genes. They are designated "D" for the dominant nondilute and "d" for the recessive dilute gene. The dilution genes are located separately from the color genes. As with a black that carries red, there is NO way to determine whether a certain Doberman carries dilution from simple observation.
Now, take a look at the color chart located at:
http://www.dpca.org/color.chart.5.html (Note that you should disregard the color of the typeface and pay attention to the color of the "ball," there are some errors in the chart!) Press the "back" button on your browser to return to this site.
A black dog MUST be either:
#3 BbDD, or
A blue can be:
#5 BBdd, or
#6 Bbdd (Storm).
A red can be:
#7 bbDD or
A fawn can only be:
If you know which type the sire and dam are, you can use this chart to predict the probabilities of the colors of the pups. You can also use the chart in the other direction, to tell you what type the sire and dam must be from looking at the pups. For example, if you have a litter that produces blues or fawns, you now know that both "parents" carry dilution. If you have two blacks that produce reds, you now know that both "parents" carry the recessive red gene.