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Sex-dimorph colored Thuringian Selfs: The cock
coloring of the grizzles in the AOC class?
A sexual dimorphism with differently colored cocks
and hens was proved in the 1930s and 1940s by W.F. Hollander for the
gene Faded. The discovery led to the Texan breed. Due to sex, cocks
have the hereditary factor 'Faded' twice, hens only single. This
causes the much stronger lightening of cocks.
 
Fig. 1: Auto-Sex
colored Texans, on the left a homozygous faded cock and on the right
the corresponding hen color for a blue hemizygous faded hen
An allele of
Faded, a gene with a similar effect at the same gene-locus, appears
to have existed in the Thuringian Forest a century earlier. This can
be taken from a report in the 'Gartenlaube' by Ludwig Storch in
1856. In his report on the country and people, he names the colors
most valued in Ruhla in the Thuringian Forest. These include colors
with similar names to those found in today's Thuringian Selfs.
Inheritance occurs in the main color varieties according to the same
pattern like at Texans (Andreas Leiß). The color effect of the
hereditary factor called 'Frosty' is only weaker. Cocks of the
Thuringian based on blue bar individuals are similarly lightened in
homozygous Frosty like hemizygous females of the Texans. Females
that only have the frosty factor due to their sex single are not or
only slightly changed in coloration. In the case of the cocks,
homozygous cocks are called blue ground colored, the females blue.
They also exist, not listed in the standard, on the basis of
blue-check pattern. In the case of the cocks, the checks stand out
slightly in the shield. Breeders call them grey-ground colored, the
hemizygous females remain blue checkered.
 
Fig. 2: Blue
Ground Colored cock and Blue Bar hen (hemizygous with only single
factor expression for Frosty).
 
Fig. 3: 1,0
Grey Ground Colored cock with a shell crest (Thomas Oschmann) and
Blue Check hen (Walter Hunger)
In the dilution one calls cocks, with genetically
bar pattern, Light Ground Colored ones. In the case of check
pattern, they are Yellow Ground Colored, the patterns are visible in
the shield. The diluted females are silver in bar pattern, and
larked as a counterpart to the yellow ground-colored in the
checkered ones. The yellow crescent on the chest indicates Lark
Bronze appears to be involved. This can be seen in the non-diluted
colors in the brown-red 'noster' there. The yellow color of the
patterns on the diluted colored cocks is surprising.
 
Fig. 4: Light
Ground Colored cock and silver hen from Frank Zetzsche (hemizygous
with only single factor expression for Frosty).
 
Fig. 5: Yellow
Ground Colored cock and Larked hen (hemizygous with only single
factor expression for Frosty).
Thuringian Selfs
did not receive a standard until 1951. In addition to the blue-,
light- and yellow-ground color classes that only apply to cocks,
silver bar, lark, blue bar, blue checkered and owls (grizzle) were
initially recognized for both cocks and hens. During a revision of
the standard, the peculiarity of gender-linkage, which was also
noticed in Germany at the time with the Texans, was partly taken
into account: the blue grounded, light- and yellow-grounded cocks
were assigned the hen colors blue, blue check, silver and lark. All
other colors, with the exception of the 'owl-like' (grizzles), were
deleted. Why the exception of grizzles? They stayed in the Standard
after objections from Thomas Oschmann. The objection was probably
given in because of the proven long tradition of owls in the breed.
This is expressed in the most popular colors of the time listed by
Ludwig Storch 1856 (Fig. 5). Named are different kinds of grizzle
like owllike, white-, black-, silver-, ground-owllike. Also, other
terms are given in old writing, that fit to the today cock- and
hen-colors of the breed.
Fig. 5: Most
popular colors in Ruhla in the Thuringian Forest at Ludwig Storch (Gartenlaube
1856)
Grizzle remained
in the
standard
in the 2004 ring binder, but with identical descriptions for cocks
and hens. No lightened cock colour, as was to be expected with
homozygous frosty cocks and the experiences in the other color
classes! Thomas Oschmann must have recognized the error back then
and at least guessed at the connections, as one could gather from an
exchange of letters years ago. Because he reported on storks being
bred, which he was not the only one to receive. At that time, most
breeders could not imagine that these storked-like cocks are
actually the cock color as counterpart of the grizzle hens.
And this
surprises in the strength of the brightening still now.
 
Fig. 6: White
stork cock and grizzle hen from Frank Zetzsche (gender related the
hen hemizygous frosty with only a single factor expression for
Frosty).
This was proven in the re-breeding of the
clean-legged Thuringian grizzles by Frank Zetzsche, who reported on
it in the 2019 German Poultry Newspaper. From the stud book and when
tracing the pedigrees, it can be seen that homozygous Frosty cocks
with the grizzle factor are lightened to light storks. The special
feature, in combination with homozygous Frosty, even when
heterozygous grizzle (Fig. 6). Unbelievers can quickly reproduce
this in their own breeding attempts. This means that grizzle cocks
in the hen color specified in the standard are not homozygous
Frosty. In breeding, therefore, other than the recognized color
varieties will fall out of them. The auto-sexing nature as a breed
is gone. The white storks, on the other hand, are the opposite of
the hemizygous grizzle hens. Paradoxical when you have to show the
color of the cock to a recognized color of the hen in the AOC class.
But maybe you'll see them there!
It will have to be found out in practice how to
breed most successfully for the best coloring of the grizzles in the
color of the cocks and hens for the exhibition. From other breeds it
is reported that permanent mating of grizzles with each other leads
to lightening. This can be counteracted by mating hens with blue
ground colored and cocks with blue hens from blue ground colored
families. If such pairings result in blue cocks, or grizzle cocks in
the hen color, then the mother comes from an outcross upon other
breeds and does not carry the Frosty gene.
Literature:
Hollander, W.F., Auto-Sexing in the Domestic
Pigeon. Journal of Heredity, 33, 1942, pp. 135-140
Sell, Axel,
Genetik der Taubenfärbungen, Achim 2015, S. 144-152
Storch,
Ludwig (anonym), Land und Leute Nr. 5 Die Ruhl und die Rühler, Die
Gartenlaube 1856, no. 27-29 in continuation
Zetzsche,
Frank, Erzüchtung der glattfüßigen und glattköpfigen Schimmel bei
Thüringer Einfarbigen, GeflügelZeitung 18/2019, S. 18f.
(Creating clean-legged and
plain-headed grizzles in Thuringian Selfs)
A.S.
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