Extension Genes

Normal Extension

'EE' or 'normal extension' has absolutely no effect on the visual phenotype of the canine, it simply means that genes are expressed at other Loci as opposed to the other genes on the E-Locus. Think of it as a 'blank gene' or a 'space filler'.

Extreme Masking Extension

Represented by 'EmEm', the gene is highly dominant, so a canine only needs 1 allele of the gene ('Em') for it to be visible.

It is believed that the masking gene goes hand in hand with the etching gene.

The masking gene can affect the face, body and tail, and come in a series of patterns.

The colour of the mask is determined by the colour genes.

Black Base Genes = Black Mask

Red Base Genes = Red Mask

Liver Base Genes = Liver Mask

White Intensity/Filtering = White Mask

In fully dominant black coloured canines who are also affected by 'progressive greying', the masking gene will not be visible until the greying phase begins.

Etching, ('et'), is when piebald patching takes on a darker border. It is only visible when Recessive Black (any gene) or Recessive Red ('ee'), Masking ('Em'), and Piebalding 'spsp' are all present in a genotype without tan points ('atat').

Extreme Etching Extension

Dominant Grizzle/Domino Extension

'Eh', is a gene modifier specific only to dominant black canines which carry the tan points ('atat') gene. The gene is dominant over every other E-Locus gene except masking.

A canine which is 'EmEh' will only show the masking, not the grizzle/domino.

Recessive Grizzle/Domino Extension

'Eg' is identical to 'Eh' above, except for the fact that it is specific only to recessive black canines.

A canine which is 'EmEg' will also only show masking, not the grizzle/domino.

Masking Extension Phenotypes

Below are some examples of how the extreme masking gene could look, the range the gene spreads is dependant on parentage and which other genes are present (piebalding, merling and harleyquin having the most random effect on the turnout of the overall pattern).

These patterns can be combined in several different ways, remember to use your imagination when designing!