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The Basic Patterns  (The A Series)

Even though the Netherland Dwarf breed standard separates the recognized varieties into five colour groups (Self, Shaded, Agouti, Tan Pattern and Any Other Variety), there are actually only three colour patterns.  The five colour groups exist in the breed standard because we classify a variety by its appearance (phenotype), rather than by its genetic make-up (genotype).  From the standpoint of colour genetics the varieties fit into just three colour patterns: agouti pattern, tan pattern, and self pattern.  The concept of 'pattern' here refers to the arrangement of colour on the individual hair shafts and to the placement of coloured areas on the rabbit.

The "ladder of dominance" below illustrates how the three pattern genes are ranked, according to their dominance or recessiveness to one another from top to bottom of the "ladder":

A = agouti pattern  

at = tan pattern     

a  = self pattern

This is an important concept regarding degrees of dominance, as evidenced by the tan pattern at, which is sometimes recessive (when in the company of agouti pattern A) and sometimes dominant (when in the presence of self pattern a).

Inheritance of the pattern genes follows simple genetic laws.  Each rabbit inherits one pattern gene from its sire and one pattern gene from its dam - a total of two pattern genes.  The rabbit might inherit two of the same pattern genes. For example, two agouti pattern genes (AA), or two self pattern genes (aa).  Or it might inherit two different pattern genes; eg one agouti gene and one tan gene (Aat), or one tan gene and one self gene (ata).  A rabbit who inherits even one agouti pattern A gene will be an agouti-patterned variety, because A is fully dominant over the other pattern genes.  Therefore, we are sure that any agouti-patterned Netherland Dwarf is carrying at least one agouti pattern A.

However, we can't tell by merely looking at the rabbit which other colour pattern gene was inherited.  The rabbit may be carrying a second agouti A gene (making it AA) or a tan pattern at gene (making it Aat) or a self pattern a gene (thus making it Aa).  Incidentally, inheriting two agouti pattern A genes (genotype AA) does not make the Dwarf anymore of an agouti than does inheriting a single agouti pattern A gene in conjunction with one of the other pattern genes.  There are no degrees of agouti-ness (or of tan-ness etc).  It's an all-or-nothing action.  If the rabbit inherits an agouti pattern A gene, it will be an agouti-patterned variety: if it doesn't inherit an agouti pattern A gene, it will be other than agouti patterned.

The example below illustrates how the pattern genes operate.  The rabbit will inherit a tan pattern at from its sire and a self pattern a gene from its dam.

   x  

Sire (tan patterned)     Dam (self patterned)

offspring (tan patterned)

As we know at is dominant over a, we know that the tan pattern at will prevail and that the rabbit will be some variety of tan pattern.  The rabbit's genotype is ata (the dominant gene is always written first, the recessive gene second).  We can tell by looking (by observing its phenotype) that the tan-patterned rabbit is carrying at least one at gene, but we can't tell by looking that it's genotype includes the self pattern a.  Either a second tan pattern at gene or a self pattern a gene has been inherited.  Since we have the parents available for observation we can see had to inherit its mother's self pattern a gene.  This recessive self pattern a gene is being masked by the dominant tan pattern at gene inherited from the sire.  Self-patterned Netherland Dwarfs are always genotype aa because any other combination of pattern genes (Aa or ata) would dominate over the more recessive self pattern, resulting in either an agouti patterned or a tan patterned rabbit.

The genetic self-patterned varieties include the Black, Blue, Chocolate and Lilac of the Self Group, plus the Seal Point, Siamese Sable and Siamese Smoke of the Shaded Group.  These 'shaded selfs' are self-patterned varieties in which other colour genes have lightened the colour in the middle section of the fur shaft.  Additionally, the Tortoiseshell is a genetically self-patterned variety in which yet another gene action has weakened the colour of the saddle from black to orange, while leaving the extremities essentially black.  Phenotypically (appearance-wise) it should be included in the Shaded Group.

 

the basic colours

colour distribution in the fur shaft

non - extension in the fur shaft

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