Re: [pyrnet] Black Pyrenees, White Newf...

["Janice Swenson" <janices@austin.rr.com>]

On 9 Jul 2002 at 5:17, Linda Weisser wrote:
> Except that piebald by definition describes an animal with white
> markings over colored.  So the white dog with black markings is not
> piebald, or at least is not exhibiting the piebald genetic pattern.

Someone I know wrote a scientific definition of the landseer coloring and I will post 
that.  The landseer coloring results from the piebald gene.  

"It has been accepted for sometime that there are 4 alleles at this
particular locus forming an epistatic series. This is simply several
alleles that can be arranged in order of "dominance". The first is the
solid (or "self") colored allele, S, which is dominant to all of the other
alleles. Second is the allele, S^i, named (after a pattern observed in
rats), the "Irish Spotter" allele. In its unambiguous expression this is
often called a mismark. The feet, much of the belly and chest are white
and there may be a white collar and there is often white on the tail.
Basenjis, for example, are homozygous for this allele. This allele is
recessive to the solid colored allele, but dominant to the rest of the
series. Next is the piebald allele, S^p. In its most typical state animals
which are homozygous for this allele show the classical "Landseer" pattern
described as ideal in the standard. The Illustrated Guide refers to the
Landseer as having the piebald color pattern and I have always taken this
to refer rather directly to the ideal phenotypic expression of this
allele. This allele is recessive to S and S^i, but dominant to the last
allele of the series, the extreme piebald allele, S^w. This is nearly a
white dog (sometimes, indeed wholely white) with usually a spot on the
head, often the eye, in which pigment is formed. The Sealyham terrier is
thought to be homozygous at this allele. This allele is recessive to all
of the others in the series, including the piebald allele." 

Janice, janices@austin.rr.com
Lana & Linsey (newfs), Sonny (pyr)  
http://home.austin.rr.com/janices/
Hutto, TX