The Basic Colours (B and D series)

Just as all the Netherland Dwarf varieties were grouped into the three colour patterns (agouti, tan and self), they are also separated into the four basic colours.  All Dwarfs, regardless of variety, are of one of four basic colours: black, blue, chocolate or lilac, all shown in the Self patterned group.  Also, several Netherland Dwarf varieties has a black, blue, chocolate and lilac colour variety (namely Tans, Otters, Foxes and Himalayans).   Even with some of the other Netherland Dwarf varieties the system of four basic colours applies, even though the variety names vary from the black-blue-chocolate-lilac litany.  We find that the Agouti, the Opal (blue agouti), the Cinnamon (chocolate agouti), and the Lynx (lilac agouti) repeat their variations of the same four basic colours.

Black B and Brown b

Beginning with the black and brown basic colours, are determined by the b-series, with only two alleles.  They are dominant black B and recessive brown b.  The ladder of dominance for the b-series is small.

B  = black

b  = brown

The breeding example below illustrates how the black and brown colours are inherited.  A chocolate buck and a Black doe have been chosen as parents of the example rabbit.  It is known for a fact that the chocolate buck is carrying two brown bb alleles and that the Black doe is carrying at least one black B allele

      X

sire (chocolate)                         dam (black)

offspring (chocolate)

Until the chocolate youngster was produced it wasn't knownthat the doe carries a brown b gene allele recessively.  Although we anticipated the offspring inheriting one chocolate b allele from its sire (who had nothing else to transmit), we now know that the second b allele came from its mother as the rabbit inherits one b-allele from each parent.  The odds were 50/50 that the dam would transmit her dominant black B allele, resulting in a black rabbit.  If that had happened, we wouldn't have discovered that the Black doe is carrying a b allele.  This is how we can discover the genotypes of our Dwarfs.  By having produced the Chocolate youngster from the Chocolate (bb) buck and the Black (Bb) doe, we now know that she is carrying a recessive b and is genotype Bb.  When we know the genotypes of our breeding stock, we can mate rabbits that will produce more offspring in the colours we desire.

Intense D and Dilute d

The blue and lilac colours are controlled by the d-series.  The d-series is referred to as dilution.  What dilution does is to change black to blue, and to change chocolate to lilac.  It also changes brown eyes to grey eyes.  (It changes orange to fawn in varieties which have orange colour in the coat).  There are only two alleles in the d-series: D and d.  

D  = intense

 d   = dilute

The dominant intense D allele has no effect on black or brown colour.    However, the recessive dilute d allele changed black to blue, or brown to lilac, whenever it is inherited in two pairs by the rabbit.  (two dilute dd alleles).  In other words,  the rabbit must receive one recessive dilute d gene allele from its sire and one recessive dilute d gene from its dam, making the resulting rabbits' genotype dd, before the action of dilution can occur.  Therefore, a basic black rabbit (who can be either BB or Bb), who inherits two recessive dilution dd alleles will be changed into a basic blue rabbit.  A basic brown rabbit (who is always bb) who inherits a pair of recessive dilution dd gene alleles will be changed into a basic lilac rabbit

Here's an example of breeding two Dwarf rabbits to see how dilution changes black to blue and brown to lilac.  

 

  X              X 

Sire (black)   Dam (black)     Sire (chocolate)  Dam (chocolate)

                              

offspring (blue)                  offspring (lilac)

We have produced a Blue youngster from our pair of Blacks.  Upon the appearance of this Blue, we have learned that both the Black sire and the Black dam are carrying one dilute d allele recessively to their dominant intense D.  Although we couldn't determine this by observing their phenotype, their production of a Blue offspring proves what their genotype is.  Even though our Blue bunny comes from a pair of Black parents, it did not happen to inherit a dominant intense D allele from either parent.  We have also produced a lilac from our pair of Chocolates, which proves both the chocolate sire and the chocolate dam are carrying one dilute d allele recessively. 

When the two dilute dd gene alleles are inherited, all colour on the rabbit is diluted, including every hair and including its iris colour.  All varieties have an intense and a dilute counterpart.  In some cases both the intense and dilute varieties are recognised though there are some varieties in which neither the intense nor the dilute state is recognised (such as in the Chocolate Chinchilla and Lilac Chincilla). 

 

the basic patterns

colour distribution in the fur shaft

non - extension in the fur shaft

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