Mangile's Pigeon Pages

Genetic interrelations of the gazzi, penciled, and
recessive white color types in the pigeon.


by Robert J. Mangile and Kerry D. Hendricks
- - - - -

In the August 1984 issue (#7), of the "Pigeon Genetics, News, Views & Comments", (PGNV&C) Mangile reported evidence indicating that the autosomal recessives "gazzi" (z) and "recessive white" (zwh) were allelic.  The focus of this 2003 report is to present evidence that a third mutant allele exists at this locus.

In a March 1981, "American Pigeon Journal" article, Dr. Willard F. Hollander mentioned that in the April 1980 issue of the French magazine, "Colombiculture", Madame Jacqueline Francqueville reported on a new recessive color mutant she called "penciled" (designated "pc") found in the "Tête Noire", (which means "black head"), an old French breed found in the area of Brive, France.   Other breeds that have the penciled mutant include Hanna Pouter, Saxon Breast Pigeon, Berne Half Beak and Czech Baghdad.  Prior to Francqueville's report, Dal Stone (unpublished) isolated the same recessive mutant which he called "palm", from the Czech Baghdad.  Various pigeon fanciers have also involved Hanna Pouters and Saxon Breast Pigeons in breeding tests.

By the early 1980's pigeon fanciers found that crosses of "penciled" (Hanna Pouter and Saxon Breast Pigeon origin) to gazzi Modenas produced irregularly marked gazzi-like F1's.  The race for a better understanding of these interactions had begun.  In Issue #3 (1983) of the PGNV&C, Paul Gibson stated: "I have some evidence of interaction (messy) between gazzi and pencilled, both heterozygous."  Debate continued as to whether or not penciled and gazzi were allelic or just linked.  In 1984 I crossed an ash-red-penciled Hanna Pouter hen with a self colored, blue T-checkered Racing Homer mongrel to begin breeding tests.  Kerry Hendricks was encouraged to join the project.  In 1997 Hendricks (personal correspondence) submitted raw breeding data from extended tests using Saxon Breast Pigeon X Gazzi Modena crosses. 

Discussion and Classification

The uncertainty in classifying pied plumage must be weighed with caution.  For example: Gazzi pied plumage is easily recognized by even the inexperienced pigeon fancier but many gazzi pigeons, particularly those produced from unselected matings, can vary from the ideal.  Penciled phenotypes vary from nearly all white plumage with some color on or around the head and vague traces of pencilling on the feathers edges, to overall dark plumage with the pencilling extended to much of the feather length with light bases, to a near gazzi-headed saddle-marked wing shield.  The lack of solid colored tail feathers is a clue in identifying penciled plumage - but not proof.

Some homozygous penciled often mimic the mostly white, colored head plumage of F1's from penciled X recessive white.  Complicating this issue is the unexpected advent of other pied factors that lighten plumage, e.g., white flights, and perhaps bronzing factors in Saxon Breast Pigeons and Hanna Pouters.  Other powerful modifying mutants like dominant opal (Od), recessive opal (o), dilution (d), reduced (r), etc., may add to the difficulties of classification.   And crosses with Modenas bring Modena bronze into the equation.  Based on a few crosses with Toy Stencil and Frill Stencil, Hendricks hinted at the possibility of a bronze or stenciling in the Saxon Breast Pigeon.

When working with a select line of birds, in spite of the difficulties mentioned above, experience with those birds helps to identify different genotypes by their phenotypic expressions.   In personal correspondence (1997) Hendricks writes: "I believe I can sort out the zpc//z or zpc//zwh phenotypes from z//z or zpc//zpc, at least when the penciled source is Saxon Breast pigeon.  I find it interesting that zpc//z looks gazzi and zpc//zwh looks penciled…"

Other pied factors are thought to interact with heterozygous penciled and produce extensive white feather bases (flash) on colored feathers.  Understanding the mode of inheritance and their phenotypic expressions without breeding tests is difficult, if not impossible.  Clearly, there is more to learn about penciled and the probable interactions with other powerful modifying mutants.  The range of phenotypic expressions of penciled may well be connected to some of these underlying factors.  There may be other mutants at the gazzi locus yet to be discovered.  Hollander (PGNV&C, March 2002, #77, p.21-22) put forth a hypothesis of six alleles at the gazzi locus.

In our breeding tests, the color-headed expressions of penciled plumage was produced often and was expressed more vividly when spread (S) was involved, i.e., producing the "black-headed" (Tête Noire) appearance.  Bronzing and stenciling, e.g., from Modenas, Oriental Frills and Toy Stencil, may alter phenotypes.  In our breeding the term "wildtype" = self, not whitened.

Mangile's records indicate that of twenty-one (21) offspring produced from five (5) matings of a penciled cock and a wildtype hen, at least five (5) wildtype hens were produced, ruling out sex-linkage.

In a 1995 partnership with Manny Gobar (G), a brown-spread-penciled cock (from Mangile) was mated to a bronze-gazzi Modena hen and they raised eight (8) intermediate F1's, in an individual coop.  A cock and a hen from those F1's were returned to me for testing, which continued until October 2001.  All of Mangile's matings and all or most of Hendricks' matings were bred in individual coops.  The combined breeding results of Hendricks (H) and Mangile (M) are represented in seven (7) types of matings - below.
 
1.  homozygous penciled  X  wildtype (Homers)
(H) 13 matings, 51 progeny; (M) 10 matings, 48 progeny - totals: 23 matings, 99 progeny; all wildtype.

2.  homozygous penciled  X  heterozygous penciled F1 from (1)
(H) 3 matings, 34 progeny,  (M) 10 matings, 54 progeny - totals: 13 matings, 88 progeny; 42 penciled, 46 wildtype.

3.  heterozygous penciled from (1) X heterozygous penciled from (1)
(H) 7 matings, 26 progeny, (M) 8 matings, 47 progeny - totals: 15 matings, 93 progeny; 73 wildtype, 20 penciled.

4..  homozygous penciled  X  homozygous recessive white (Homers)
(H) 1 matings, 10 progeny, (M) 4 matings, 19 progeny - totals: 5 matings, 29 progeny, all intermediate.

5.  heterozygous for penciled & recessive white from (4) X  homozygous recessive white
(H) 1 matings, 11 progeny, (M) 1 matings, 6 progeny - totals: 2 matings, 17 progeny; 9 intermediate, 8 recessive white.

6.  homozygous penciled  X  homozygous gazzi
(H) 2 matings, 7 progeny; (M)(G) 1 mating, 8 progeny - totals: 3 matings, 15 progeny; ALL intermediate.

7.  heterozygous for penciled & gazzi from (6) X   heterozygous for penciled & gazzi from (6)
(H) 2 matings, 17 progeny, (M) 1 matings, 28 progeny - totals: 3 matings, 45 progeny, 10 penciled, 25 intermediate, 10 gazzi.

Conclusions

With regards to the combined data above, twenty-three (23) matings of "penciled X wildtype" produced ninety-nine (99) F1's, ALL (100%) wildtype or self-colored.  Fifteen (15) matings of "penciled X wildtype F1's" produced ninety-three (93) F2's of which seventy-three (73) were wildtype and twenty (20) were penciled.   The 73:20 ratio is close to the expected 3:1 ratio.

 Three (3) matings of "gazzi X penciled crosses" produced fifteen (15) F1's, ALL (100%) intermediate gazzi-like, suggesting an interaction.  Three (3) matings of "penciled X gazzi F1's" produced forty-five (45) F2's.  Though classification of some F2's was arbitrary the 10:25:10 ratio (10 penciled, 25 intermediate and 10 gazzi) is in line with the expected ratio of 1:2:1 for alleles.

If penciled and gazzi were only linked and not allelic the F2's should have included a percentage of crossover "wildtype" offspring relative to the closeness of the linkage.  Of forty-five (45) "gazzi X penciled" F2's produced NONE were wildtype or self-colored, supporting the likelihood that penciled and gazzi are allelic.  It follows that if "gazzi" and "recessive white" are allelic "penciled" is a third mutant allele at this locus.

Madame Jacqueline Francqueville used the genetic symbol "pc" for penciled. That symbol should now reflect its allelism at the gazzi locus; therefore, the genetic symbol for penciled should be "zpc".
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