Marking Patterns and Modifiers

All pigeons come equipped with two genes for pattern. These various pattern gene possibilities are c for Barless, + for Bar, C^L for Light Checker, C for Checker, C^D for Dark Checker, and C^T for T-pattern or Velvet.  They are listed here in their order of precedence; with Barless being the least dominant and T-pattern velvet the most dominant.   Since two genes for pattern are always present, the possibility that these two may not be of the same genetic pattern may very well exist.  When this happens, the bird's phenotype appearance will be of the more dominant pattern for the gene combination for that pair.  For example: (c//c) being homozygous for this gene factor is naturally a Barless in phenotype while (c//+) being heterozygous for both the barless and bar factors, becomes a Bar in phenotype as the gene for bar in this combination is dominant over the barless condition.  Continuing on through this series the combination of (+//+) would also be a Bar in phenotype but here it is homozygous; next  (+//C^L) a heterozygous Light Checker;  (c//C^L) also a heterozygous Light Checker; (C^L//C^L) a homozygous or pure Light Checker; and so it goes on up through the order of precedence for each pattern.

We need to have a starting point in order to classify the many various genetic factors of our pigeon's gene pool.   For domestic pigeons we use the wild Rock Dove as our starting point.  Anything that deviates from that standard is said to be a mutation of some kind.  OK let me repeat that in another way.  It was from the wild Rock Dove species that all of our domestic breeds originated.  Rock Doves are normally found to be blue bar in their appearance.  For that reason we refer to this simple blue bar pigeon appearance as being "Wild Type".    Not necessarily a wild bird but like one in color, pattern and all other visible attributes.  These wild type birds in appearance are the pigeons with the basic set of genes which will produce a blue color, bar pattern, normal feathered etc. being normal for the wild form.   In short, there are no modifying genes there to alter there appearance from that of a Rock Dove.   

Thus birds that are seen as a blue bar with the attributes of a Rock Dove are said to be of wild type even though they are of domestic stock. Change any of these wild type genes and you would be modifying it from the "Wild Type" and the pigeon would no longer be a normal blue bar Rock Dove.   It becomes something else, either in color, pattern, size, shape or performance capabilities. In other words, the genes that make any pigeon different from a common wild blue bar are referred to as mutations from the wild type.  Thus wild type becomes our starting point for classifying all gene mutations.

Barless Pattern          Modified for both Barless Pattern and brown color, left.    Modified Barless Pattern on wild type Blue color, right .     Bar Pattern     Wild type Bar Pattern on modified brown color, left,     Wild type for both Bar Pattern and Blue color, right. Ash-red on wild type Bar Pattern Checker Pattern     Light Check pattern in brown, left; checker pattern in blue, center; and dark checker pattern in Ash-red, right. Dilute blue check pattern (properly called a Silver Check or Dun Check) is the result of the modifying gene called dilute.  Here the dilute gene changes the color from blue/black to an almost brown check color on a silver background.  Note that dilute will modify color but not the pattern. T-Pattern or Velvet T-Pattern: It gets its name from the small light colored T in the check pattern      T-Pattern Velvet with Kit Bronze left,   Blue T-Pattern right.

Complex Modifiers Now we all know that our pigeons come in many more colors and patterns than just those that are shown above.  We find birds with white markings while others may be solid black, red or even white.  We have yellows, gold’s, khakis and duns.  We have grizzles in various colors and we fine some birds displayed as indigo and opals just to mention a few example of these modifications.  These additional phenotypes or appearance forms are due to the many genetic modifiers known to exist in our birds gene pool.   Modifications to the pattern series would be the barless and checker patterns and their presence simple means that a wild type bar gene has been altered into one of these other patterns.  All other forms of pattern change are modifications in addition to and not in place of, these basic pattern forms.  While other modifiers  may alter our birds outward appearance by replacing a gene somewhere in the wild type gene pool, they do not in any way eliminate the various patterns shown above.   Always remember that when a birds basic color of wild type blue or the pattern forms listed above are hidden or masked, these changes have not eliminate or replaced their true genetic color or pattern.  They have simply modified or masked them in some way resulting in different phenotype.  Such modifiers can hide a birds basic pattern completely; they can alter a birds color and leave the patterns unchanged or they can do both as in a solid blue, brown, red, white, yellow or gold etc. .   Regardless of what the modifier’s genes have done to the outward appearance, the original pattern and basic color inherited from its parents is still genetically there and can be transmitted independently of the other modifiers to their own offspring.      The black pigeon above on the left is a blue bar modified by the spread gene to become a black.   If you look closely you can still see the outline of the bar pattern on its wing and tail.  Here the normal genetic pattern is hidden by a color change from blue black to all black.  Genetically the color hasn't changed from blue to black because in pigeons the color we call blue is really a form of black.  Here the birds color is simply displayed in a different fashion, due to the effects of the spread gene.  Spread changes the pigment distribution and in so doing has changed the way light is reflected off the bird (lessened) and therefore is seen by your eye as black.  The bird on the center is a genetically a blue checker and its normal blue checker phenotype has been modified by the mutation known as Tiger Grizzle.  We know she is genetically a blue check based upon her blue/black color shade as the checks are the reason for the amount of dark markings on the wing shield.  Tiger Grizzle depletes pigment totally in some feathers while not at all in others leaving the bird in a mottled phenotype.  In addition, Tiger Grizzle does not affect the tail area . The hen pigeon shown above on the right is a recessive red (e//e) with white, dilute(d//d), blue(+//+) and  check pattern genes (C//C).   So under all of these modifiers is a blue check but what you see is a golden yellow and white bird.  Here true basic pattern and her true blue color are being masked but none the less, they are genetically still there.