Reduced (r) and Rubella (rru)

Reduced and Rubella are two rare color modifiers that share the same genetic location on the Z sex chromosome known as the r locus.  Actually there are three possibilities at this chromosomal position but of the three only these two are considered uncommon.  The more common of the gene possibilities found at this location results in a display of normal color intensity or what we call wild type.  This page deals only with the much rarer occurrences of reduced and rubella.  Of these, the first (reduced) originated in flying roller in the USA and has subsequently been moved into several other breeds; while the other, (rubella) has only recently been found in German racing homers.  Like reduced, rubella is now slowly finding its way into other breeds; at the hands of various color breeders.

The following is an excerpt from Joe Quinn’s "A Pigeon Breeders Notebook" c 1971.   It is an excellent book which I highly recommend.  Every student of pigeon genetics should have a copy.

"A boy whom Carl Graefe had helped  with a start in rollers, brought him a pair of birds and asked Carl , "What color are they?  " Carl answered, "I don’t know."   The chance mutation, coupled with the odds against it being reproduced in a homozygous cock, seems fantastic, when we consider that the pair is presented to one of the few men who might recognize their value.   An attempt was made to trace the birds, but to no avail."   However from these first few, all pigeons that today carry the reduced color go back to these original birds. 

As I previously stated, rubella was recently found in a German racing fanciers loft.   To my knowledge, only a handful of rubella pigeons have been imported to the United States, Dr. Paul Gibson being the primary source and point of contact.  I had one gifted by Dr. Gibson but she escaped before I could breed from her.  My plan was to put her with my reduced homers and study the slight differences between the two alleles.  Sometime later Paul gave me another but this cock was to old to continue breeding.  Perhaps someday I’ll get another chance. 

Note in the case of Reduced (r) and Rubella (rru) only lower case letters are used.  Genetic symbols in lower case always denote recessive traits while an uppercase symbol would denotes a dominant.  Reduced and rubella are both recessive to wild type.   Since reduced was discovered first, the locus where the two reside was named for the reduced gene, i e. the r locus.  Since reduced is recessive to wild type, both the locus point and the gene are symbolized as lower case r.   Now along comes the new genetic find of rubella and we determine that it is an allele of reduced.  Well, we must give it a symbol and since it is at the r locus this symbol must start with a lower case r and receive a superscript to denote its name and dominant or recessive characteristic.   As it turns out the letters ru were selected for rubella and since it is recessive to the reduced gene at the r locus the superscript letters ru will also be written in lower case.  Had rubella been dominant over reduced the superscript letters would have been capitalized.    In that case, the genetic symbol would be (rRU) and not the (rru) that we use today.

That is very interesting you say but what does it all mean.    Well for starters since reduced and rubella are both sex linked genes on the Z or sex chromosome only a cock bird can be heterozygous for each possibility i.e. r// rru and should that occur the bird will always express as a reduced and not a combination of the two.    

What follows is a brief description of reduced (r) and rubella (rru).   Photos for the rubella homers were submitted by my friend Jens Stinner of Birken Germany    Photos of some of the reduced birds were taken at my loft in Georgia before moving here to Duncan South Carolina.  Others are as noted.  Since reduced is the first of the two noted, lets begin with its description.    



Reduced lightens the intensity of pigment by reducing its amount.  On a basic blue color pigeon, the reduced factor produces numerous pastel pink and or buff colorations for the birds various marking patterns.    The reduced mutation was first noted by Carl Graefe when a young boy brought a flying roller of strange color to him asking what its color was.  Carl being a keen student of pigeon genetic knew that this was something new and retained the bird for further study and breeding tests.  It was he who gave it the name reduced.   The other two alternatives for this gene are intense i.e. non-reduced wild type (R+), and rubella (rru) which is a new European mutation which is discussed below.  In other words, both reduced and rubella represents a change from the normal intensity for pigment to lighter amounts.
If you will recall from Chapter 1 - Sex, Chromosomes and Genes  a hen can only carry one Z chromosome.  Therefore it is only possible for her to have one reduced series mutation at a time.  The same is true for the other mutations found on this chromosome such as dilute or d grouping and or the almond ST grouping.    As a point of interest, if we rule out the wild type possibility for either of these series and only deal with the mutation possibilities we find that a hen could have a reduced/pale or a reduced/dilute combination but never a combination of both pale and dilute or rubella and reduced.

On the other hand, a cock bird always carries two Z chromosomes. So it is possible for him to carry both pale and dilute in combination with reduced, rubella or Intense.   However, in these cases only the more dominant will be displayed in combination with the others.   Example being a reduced//rubella combined with a pale//dilute combination and should this happen only the reduced and the pale would have any impact on the outcome since they are the more dominant of their respective grouping.   I'm not sure what would be the result but my guess is a very light pastel.

The following are photos of some of my reduced blues.  Reduced can also occur with either of the other two basic colors, brown and ash red but sadly I don’t have any to show at this time .


A reduced blue bar left, with reduced white bar on the right

A reduced blue bar has all its color pigments reduced with the effect of turning the blue into a gray cream while the bodies normal black markings become a pink/rust like color. What normally is a black tail bar fades into a gray.   The birds hackle or neck a bit darker than the wing shield with a pinkish green luster.   A pastel metallic cast is often seen and desired.   Compare the metallic look around the head and neck the birds above with the more normal blue look of the rubella blue bar shown below.  Also note the faint white bars on the above bird on the right.  Not sure why this difference but I do know this hen also carries the modifier know as dirty (V).  This may account for the difference in phenotype.  Reduced like so many other color modifiers needs more conclusive study.


Reduced blue check

This bird here, a hen, is a splashed blue checker reduced with white flights.  She is a good example of reduced blue with the typical  pinkish hue for pattern marking and gray tail with slightly darker tail bar.  Also note the metallic color of the neck.  Photo provided by Jens Stinner.


Reduced blue t-pattern or velvet left, reduced blue white bar right.

Have you noticed the normal black wing shield pattern markings are modified by reduced to display as a very pastel pink color with light gray tail and under side.  The more pattern displayed the more pastel pink seen.  Both cocks and hens are very striking in color.   

Reduced can also be variable with some displaying white bars similar to that found with dominant opal.  See photo upper center.  White bar reduced patterns do occur and are normally healthy birds; however, there are exceptions with white bars.  My experience has been that  a reduced white bar with white tips on the ends of both its wing and tail feathers along with a white head cap will be a very weak bird and live no more than six months.  Why, I do not know, but I believe it’s the result of combining this mutation with other mutations that when mixed weakens the birds system resulting in an early death.  For this reason, I do not recommend combining reduced with other color modifiers such as dilute or opal.


Reduced blue spreads or what some would call reduced black.

When in combination with spread, see photos above, a reduced blue will have a phenotype very similar to that found with spread blue dominant opal or spread blue recessive opal or even spread blue rubella.  At first glance it is very difficult to distinguish between them as they all display that dark lacing effect on the outer edge of the feathers.  The bird on the left is from Jens Stinner of Birken Germany ; the other, on the right is by Karl Rau , Rare Color Homer Loft of Maine.

Now let’s turn our attention towards rubella, the other mutation in this series.  In my search for information I have only been able to find one article that explained how rubella was found and how it relates genetically.  It was originally published in German by Gerhard Knopf who is, I believe, also responsible for the genes discovery.   My friend Hans Windgassen, a retired high school art teacher and pigeon flyer made the original English translation for the article and I added a few slight modifications and updates as posted here.

Rubella - A New Color Mutation by Gerhard Knopf

German breeders of racing pigeons normally select for homing ability and flight performance.  For them, color varieties are of secondary importance.  When a strange or odd color does occur, its labeled "Fehlfarben" which translates to miss color or odd color and its genetic makeup is of no concern to the breeder.  Normally the reason for such odd colors is the combination of multiple genetic modifiers working in concert with each other to produce an odd or uncommon color phenotype.  It is seldom that the genetic makeup cannot be traced back to a known genetic source or group of color modifier.   On rare occasions, however; there are some that cannot and these are often the result of a new mutation.

Discovery presupposes some research to prove genetically what it is and how it falls in the known order of genetic rules.   A few years ago, such a bird of unusual coloration appeared among my stock of homers.  This squab was short downed and further recognizable by a light colored beak, when feathered its yellow-to-red plumage in the crop area and by reddish-brown color tones on its bars and checker pattern areas.  Its overall blue body color was lighter than what is generally seen in that base color.   The checker pattern on the coverlets, as well as that of the bar region of the secondary’s was a reddish-brown color with only the outer rim (edge) of the feathers marking pattern being blue. 


The bird was a hen.  A stronger coloration occurred after the molt.  I assumed it was recessive opal, as both parents were of the blue/black base color with a well-expressed tail bar.   A mating of this assumedly recessive opal bird to a known recessive opal cock (all test matting done in isolated cages) did not result in opal as expected but in normal blue progeny.    This pointed to the phenomenon or possibility that differing genes existed among some racing homers which could produce a recessive opal phenotype or mimic in appearance.   This in turn led to further test matting of three successive generations, details of which I will not go into here. 

The results of these test matings led to the conclusion that the new mutation was a recessive gene and that it is located on the sex chromosome.  The effect of this gene on adult birds is as follows:

  • The blue color is lighter than usual on a blue/black base color.
  • The pattern areas (bars or checker) are of a reddish-brown coloration, only the outer edges of the feathers are blue. 
  • The usual coal black tail band is lightened among hens according to base color, among cock birds white-gray to almost (all) white.
  • The primaries appear light gray to silver-gray, the outer edges are markedly darker (pictures above.)
  • Among birds of a brown base color only a very weak reddish coloration occurs on the bar or pattern areas which is similar to a rust color.
  • Insert (At present no data is available for how it appears on ash red.)
  • In connection with Spread an interesting change occurred in that the coloration was distinctly different between male and female birds:
    1. The hens were colored mouse-gray to dark gray, while the cock birds were of a light silver-gray coloration.
    2. In both sexes there is accordingly a darker edging of the coverlets and the flight feathers. (picture on lower left)
    3. Both female and male birds showed darker edging after the first and second molt.



Photos for the rubella homers were submitted by my friend Jens Stinner of Birken Germany.

Because this phenotype is so similar to birds with the reduced color gene including those in combination with spread, it was obvious that a test mating had to be done to learn if they were somehow related.    The results clearly show that both reduced and rubella are alleles of each other, and that of the two, reduced is the more dominant!    

This surprising and fascinating discovery ended here with the selection of a name.  Since opal and rubella are related and since the stone known as Opal has a glassy metallic sheen that reflects light in many colors the name "Rubella" was chosen.   Rubella is a red-brown mineral without metallic sheen, whose variation in color tone or nuances is similar to that of the described checker and bar coloration.  

In keeping with the proper selection of genetic symbols the lower case symbol rru was given to denote a recessive gene at the r locus. 

At this time and according to contemporary research, three alleles occur on the sex chromosome among pigeons for the so called b-series or base colors.  They are (b) for brown;  (B+) or simply  (+)  for wild type blue/black; and (B A) for ash red.   The many color modifiers also found on the sex chromosome include the ST series with the Almond factor (ST) and its alleles [Hickory (STH); Qualmond (STQ); Faded (STF); Sandy (STS); Frosty (STFr ) and Chalky (STC)].  The d-series with the dilution factor (d) and its allele pale (dP) pale and extreme dilute (dex); as well as the r-series with the reduced factor (r) and its new found allele rubella (rru) may also to be found theer.  By Gerhard Knopf

Interested breeders may contact the author Gerhard Knopf at: Alter Uentroper Weg 253, 59071 Hamm, Germany Gerhard Knopf

Again I would like to thank both my friend Hans Windgassen for his work in translating the above article and Jens Stinner of Birken Germany for the wonderful photos of his rubella birds.

Now to bring this to an end, we have another very nice Rubella blue check submitted by Arnau Constans of Spain.  Note how similar this bird is in phenotype to a recessive opal.   While Rubella and Recessive opal when on the basic color of blue may look almost identical, genetically they are miles apart.  Rubella being a sex-linked recessive and recessive opal being an autosomal recessive.    The differences between a sex-linked recessives and an autosomal recessives is  in the way they are passed on to their offspring.   Each follows a different set of rules in the process and outcomes.



Next Page - The Almond Family” or Almond (St); Qualmond (StQ); Faded (StF); Hickory(StH); Sandy(StSa); Chalky (StC):and Frosty(StFr)

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Copyright 1999 by Ronald Huntley.
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