Naked Neck  Nn//Nn

By Dina Mergeani
Constanta, Romania
Photos by Dina MergeaniAlex Marean, Florin Oprea and Octavian Sarafolean.

Two very similar pigeon breeds; the Spanish Naked Neck and the Romanian Naked Neck, each display a very rare condition known as Naked Neck.  This rare mutation manifests itself as a patch of bare skin around the neck i.e. the absence of neck feathers; and is the main phenotypic trait for these two very rare breeds.   All of the birds shown here are of the Romanian Naked-Neck variety.   Also take note that the birds shown here are of some form of ash-red.  Apparently ash red pigmented birds are able to produce this naked neck condition quite easily; whereas no known browns and only one or two wild type blues were ever known to display this rare genetic condition.   The original standard called for the naked neck birds to be of the darker, nearly solid, T-check or velvet wing shield pattern, with pearl eyes.

Naked neck pigeon ash-yellow  t-pattern (BA, d//., CT//CT, Nn//Nn)
Naked neck pigeon ash-red t-pattern  (BA//?, CT//CT, Nn//Nn)

Close up photo of the same two birds shown above.

The absence of neck feathers is not a total one.  If you look closely you will see the feather follicles are functional and they are easily observed after each molt; and for each follicle there is a feather’s rachis.   At some point during development the feather's normal  growth stops, atrophies (undergoes a degeneration) and falls off.

Two Naked neck ash-yellow pigeons.  

Degeneration of the affected feathers is quite complete.  Rarely are these atrophied feathers seen after the molt. Only new replacement feathers, which have yet to go through the process, are visible in this naked area.

Two Naked neck, ash-red pigeons in molt condition.  

This absence of neck feathers is determined by an incomplete dominant gene known as Naked neck and symbolized as "Nn".  An incomplete dominant gene is one that will express itself completely when in the homozygous condition but expresses only partially in the heterozygous state.   In addition, the Na gene has a monogenic transmission characteristic; which means it is controlled by a single pair of genes.  Therefore, a cross between a naked neck pigeon symbolized as Nn//Nn and a bird of normal neck plumage +//+ will always result in heterozygous Na//+ first generation "F1" youngsters.  These heterozygous F1 youngsters will only be partially naked in their neck area, as depicted in the two pictures below.  A further crossing of these F1 x F1 heterozygous partial naked neck youngsters (Nn//+ x Nn//+) will yield F2s of the second generation; resulting in a ratio of proportion in a range close to 1:2:1 among these F2 offspring.  This means, on average, you will have 25 % being homozygous normal plumage (+//+), 50% being heterozygous partly naked neck (Nn//+) and the remaining 25% being homozygous (Nn//Nn) or pure for the naked neck condition.  This 1:2:1 ratio demonstrates Na to be an incomplete dominant, autosomal gene.

Ash red partial Naked neck left, Ash yellow partial Naked neck right.  

The two F1 heterozygous Nn//+ youngsters above, show their partial naked neck condition which resulted from a cross between a pure Nn//Nn naked neck bird and a breed pure for normal feather neck +//+.   The first bird on the right is a Romanian Naked neck X Takla (a Turkish normal feather neck breed).  The bird on the left is a a pure Romanian Naked neck X a Orbetean Highflyer (another Romanian normal feather neck breed).  

Occasionally you will find a youngster with an incomplete naked neck condition in the nest; even though they were hatched from two homozygous or pure naked neck parents.   Typically, these youngsters, which appeared to be incomplete Nn//+ phenotypes when leaving the nest, will molt to their true or complete Nn//Nn naked neck phenotype with their first adult molt.  Example, as seen in the two photos below.


In addition, we can find examples of naked necks where the gene's naked effect extends all the way up unto the top of the birds head.  Shown below with photos of the same pigeon showing its rear and side head views.

Naked neck pigeon ash-red t-pattern  (BA// BA,  CT///CT Nn//Nn) extending up onto the top of the head.

These extending characteristics i.e. expanding of the naked areas up onto the head, as shown above, do emerge occasionally and especially so in lofts with a high degree of consanguinity; meaning the individuals descended from a common ancestor or in this case are closely related.   This helps to explain why it is so difficult to transfer the naked neck phenotype to other pigeon breeds; or to introduce new patterns and or colors into the existing naked neck breeds.  This degree of difficulty, in bringing in a new feature, strongly supports the idea that the emergence or ability to display a completely naked neck may require other genes to modify or modulate the naked neck effect.  Ash red being one such possibility as an enabling gene.

After having made an out cross with a normal feathered bird, it takes at least three generations of back crossing to stabilize this Nn effect; and to be able to produce a good naked neck feather trait expression or phenotype in the process.  Therefore, when introducing a dominant gene, such as the spread gene "S" (one which we know is not a part of the Nn breed’s normal genetic makeup) not only are we dealing with moving a new trait from a normal feathered bird and restoring the proper Nn phenotype; we are also faced with retaining the newly introduced S gene while going through the three generation back crossing process.

Re-stabilize the naked neck phenotype to its full expression, when introducing a recessive trait, is even more difficult and requires even more back crossing to reach the desired goal.  Below are two such examples of the spread gene having been introduced into the Romanian Naked Neck breed.

Naked neck pigeon ash-red Spread T- checker(BA//., CT//CT, S//+) = a Strawberry
Naked neck pigeon ash-red Spread T- checker  (BA,d//.,  CT//CT,  S//+) = a dilute Lavander

One of the surprising facts about the Nn gene’s performance, is the fact that it will not result in a feather de-pluming effect of the neck area, when the feathers there are white.  In other words, whenever there is white plumage in the neck area, the Nn gene seems to have no effect on de-pluming the neck, even though it is homozygous for this Nn//Nn condition. 

The white pigeon shown below is an example of this.  Its two ash red parents are both homozygous Nn//Nn naked necks.  However each parent bird carried one copy of the recessive white zwh gene; and as a result this youngster is genetically a BA//?,  CT//CT , zwh//zwh, Nn//Nn  and is therefore a white phenotype even though its genotype is homozygous for Nn/Nn.  The Nn effect was either blocked by the presence of white or by the absence of red pheomelanin pigment.  Either way, the presence of the white zwh//zwh plumage disrupts the Nn effect.  

White Naked neck pigeon without naked neck out of nest (BA//?,   zwh//zwh,  Nn//Nn)

This is also true for other white neck markings, such as pied white or white crescent marks when present.  Note the white feathers in both the ash red and ash yellow birds below.  Each has a few white neck feathers displayed. The one on the left, where its normal white crescent marking is and the other on the right with its white pied markings.  Keep in mind that some Romanian breeds, closely related to these Naked neck pigeons have white crescent or white collar markings.

A Naked neck ash-yellow with white pied marks on the left and a Naked neck ash-red with a white crescent showing on the right

The same ash yellow pigeon, seen again below on the left, shows a couple of white pied feathers on the neck and again at the back of its head; while the ash red on the right shows 
white spots on the chest and again on its abdomen.  This abdominal white spot is frequently seen in association with a white patch in the neck crescent.


The best support for this is demonstrated by the two photos of the same pigeon below.  This naked neck F1 has a white patch on the right side of its neck due to a pied marking inherited from its pied father.   Like all naked neck F1, heterozygous for Nn//+ it has a partial featherless neck.  In this case, the area is located on the left with some red plumage but not to the right where there is a abundance of white plumage.

F1 Naked neck pigeon X Magpie Iassy tumbler with a white crescent (Nn//+), pied)

Since a feathers color is produced when melanic pigments transfer from melanocytes to keratinocytes surrounding the feathers insertion point and then from keratinocytes to growth feathers.  However when the melanocytes are missing in some white areas of the body, such as the result of some pied genes, we conclude that the effect of this "Naked neck" gene is conditioned or dependent upon the presence of melanocytes to display. This effect could consist in an abnormal functioning of these melanocytes characterized by production of substances not yet known; i.e. a substance blocking effect of an enzyme that is involved in the growth of feathers. This substance then, when transferred to the surrounding cells with melanic pigments, is thought to inhibit the growth of feathers in this area of the body, thus causing the appearance of the naked neck.   It is quite likely that just melanic pigments are those who have a "toxic" effect on the growing feathers. Thus, the "Naked neck" gene effect would be to transform these melanic pigments in the keratinocytes surrounding the point of growth of feathers to a blocker of a feathers growth.  According to the above particulars, it is unlikely that we can get bull-eyed white pigeons (homozygous for the Recessive white gene) that would also have a naked neck phenotype.



The two photo above  were taken by me at the Erfurt show in Germany.  They show examples of the new addition of the bar pattern; now being added into the Romanian Naked-Neck breed.  Originally the breed standard allowed for only the darker wing shield of the  T-pattern, but recently breeders have begun to cross in other wing shield patterns.  As I said before, this is a process that takes three or more back crosses to complete before the naked neck condition is seen in its full phenotype.  Attempts are also being made to introduce other colors, such as the F1 black youngster shown below.  However, you should notice that this black F1 heterozygous Nn//youngster does not display as a partial Naked neck like the typical heterozygous ash red F1s do.  This differance may indicate that the naked neck effect for the various melanic pigments (eumelanin brown and black and  pheomelanin red) as they transfer from melanocytes to keratinocytes each operates differently.  

We know that all visual colors as seen by our eyes is made by reflection and absorption of light in the pigment granules.   The pigment granules found in the feathers of our pigeons have a combination of both eumelanin and pheomelanin; and that the color we see is the result of their different concentrations.   The colors brown, blue and black which we see in feathers is due to the higher concentrations of eumelanin. Bronze results when the levels of eumelanin is reduced and pheomelanin increased; while the color red results with the grater abundance of pheomelanin.   It is certainly possible, that in order to produce a good naked neck effect, the melanic pigments must be higher in concentration of pheomelanin or conversely a lower level of eumelanin.   This may explain why ash red  pigmented  naked necks are so prevalent, while birds of the brown and or black variety are hardly know to exist.   In fact, the only reference I have been able to find, of blue and black naked necks, comes from an old Romanian book dated in 1961.   It is possible that these eumelanin pigmented birds had to be homozygous Nn//Nn in order for it to display their naked effect.  

Today we know that Nn will partially display on recessive reds, as seen in the photo (lower right) taken by Octavian Sarafolean at a pigeon show.  Unfortunately, this bird would not stand still for a good clear shot.  However, recessive red is primarily pheomelanin just as is ash red, so it is not surprising that this recessive red naked neck phenotype is also possible.  


Without a doubt, there is still a need for much more testing of this rare, incomplete dominant mutation known as Naked neck and symbolized Nn.   There remains the questions of "Is it possible for a homozygous eumelanin color to display this Nn effect"?   Are these old claims mistaken; or for that matter are they even of the same genetic result?   These and other questions will be answered some day.  Until then, we need to continue testing.

An additional point of interest is that another, even more rare, naked mutation has also been reported in domestic pigeons.  This naked mutation is total in its naked effect.  In other words, the birds are without any form of body feathers.  They were completely naked and as such could not copulate for reproduction and required artificial insemination to reproduce.  This mutation has since become extent.  This total naked effect was a simple recessive trait and was referred to as Naked.   As a recessive gene trait, this totally naked body mutation is symbolized with the lower case "na"; while our somewhat more common naked neck mutation is symbolized with an upper case “Nn” which denotes it being a dominant trait.   Lower case always denotes a recessive to normal while an UPER case a dominant trait over the normal wild type condition.  

A similar naked neck mutation is also known to exist in our domestic chickens, where it is symbolized as Na and not Nn as it is in our pigeons.  This chicken mutation is desirable to the meat producers, as it has the added advantage of producing a larger breast mussel for the same food intake.  

My original Naked Neck article was written several years ago, in the Romanian language.  In that article, I used the upper case genetic symbol Na for this mutation; and at that time, was not aware of the naked body mutation, symbolized as lower case na, by Cole and Owen back in 1944. Had I known that, I would not have selected Na as my symbol; even though Na is used in chicken genetics for a similar naked neck phenotype. Instead, I believe I would have chosen Nn. That however, is water over the dam and we cannot turn back the clock.

Subsequent to my work, Hein van Grouw wrote his very fine article on naked neck pigeon breeds for Aviculture and also published his Pigeon Genetics book in early 2009.   For his work, Hein chose the symbol BN, for Bald Neck, as his choice for a genetic symbol.   Hein’s work and mine were done independently of each other.  We may have differed in our choice for genetic symbols but we are in agreement which our independent findings.  He having chosen BN for Bald Neck, while I originally had selected Na for naked neck.

Hein and I have since become good friends and I agree with him in that we need to eliminate any chance for confusion over the symbol chosen.  Both BN and Na, as genetic symbols, could possibly work but each has its own drawback.

With BN for bald neck, we are not describing it as it is normally referred to. In addition, almost all of the literature written on this mutation describes it as Naked Neck. Thus, to be in keeping with the genetic symbols naming rules, it should be named as it is commonly known or described; and it is known as a naked neck condition and not a bald neck condition.

While Na is in keeping with naming it in the similar fashion as done for the chicken naked neck; we would then have a symbol conflict with another very rare pigeon mutation known simply as “naked”.  Naked as a pigeon mutation is for a totally naked body phenotype; and its symbol is na. This naked body mutation is recessive to wild type and therefore is symbolized as "na" in lower case.   So by using Na in the upper case for naked neck in pigeons verses na for naked body in pigeons, we could cause confusion, since the proper symbol for wild type at the naked body na locus is Na in upper case.

Now even though we could substitute na+ as the wild type symbol for normal naked body trait, confusion between the proper usage of these two symbols may well result. So in keeping with the long held naming tradition of keeping the selected symbol understandably plain and self describing; and with the advice of others, I have elected to use Nn as my symbol of best choice.

I would like to extend my sincere thanks  to Ronald Huntley for his helping me with my translation of this article, from my native Romanian tong into English; for the most helpful bits of information he has provided and for garishly posting it here on his web site.  

Thank You Ron.  

By Dina Mergeani
Constanta, Romania

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