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12-10-2010 04:18 PM #1
The Genetics of Breed Color In The American Pit Bull Terrier
The Genetics of Breed Color In The American Pit Bull Terrier
by Amy Greenwood Burford B.S.fficeffice"
One of my responsibilities as a member of the staff of the American Dog Breeders Association is to be the ‘color expert’. I believe that my many years of experience in the breed, as well as the opportunity to have grown up in a true ‘American Pit Bull Terrier’ family. has given me the exposure that it requires to know the descriptive terms to describe the many diverse colors in our breed. The color description that is placed on your ADBA registration papers does not in any way attempt to depict the genetic makeup (genotype) of the individual dog. Instead it is a description of the dogs actual color that you see (phenotype). This color description is used for identification only and in many cases does not predict what color combinations the individual dog will produce in its offspring. Over the course of the last few months, I have received a surprising number of questions concerning color and the genetic inheritance of color. Questions such as: 1. The blue color in the APBT in the past was very rare. How are so many kennels now producing blues in such numbers? 2. It is possible to produce a puppy with a black nose, when both parents have red noses? 3. Where does the chocolate coloring come from? 4. How did I produce a brindle from a line that has never had brindle dogs? In my review of the genetics of color in the American Pit Bull Terrier, I will review a few of the principals of genetic inheritance in general and look at the research that has been done in the field of color genetics in our breed in an attempt to give our readers a better understanding of color genetic as well as provide answers to the above questions. GENETIC PRINCIPALS http://www.adbadog.com/p_pdetails.asp?fspid=101 The Color-Type Method Of Breeding
SPORTING DOG KENNELS
Constructive Breeding II – The Color-Type MethodConstructive Breeding II – The Color-Type Method
by Lawrance D. Mahomes
For thousands of years, breeders of plants and animals have used breeding methods to produce favorable combinations of genes. These “genetic engineers” have produced most of the economically important and Influential varieties of flowers, vegetables, grains, cows, horses, cats and dogs.
Breeding with the Color-Type Method – one must start with or acquire foundation stock or breed (create your own) foundation stock from the absolute best Genetic Gene Pool available. Then implement the Color-Type Method of breeding for the expeditious development of a line/strain/family for this is one method by which one who is not well versed in genetics can create a line/strain/family. Breeding with this method one can segregate desired traits and fix those traits quickly. This is achieved by breeding the same colored and type (genotype) specimens within a line/strain/family (close bred from the same stock), black to black, brindle to brindle, red to red, white to white, etc.., remember starting with a good foundation stock is essential. Once the desired characteristics and conformity are attained, one should line-breed, producing exceptional progeny (off-springs) with consistency.
The Color-Type Method in detail – the breeding of like characteristics, most off-springs (siblings) of the same color and type, carry close genetic make-up (genotype), hence the Color-Type Method of breeding. By segregating like characteristics and breeding the like characters together, the traits are fixed with rapidity (genetically fixed). This is how distinct lines/strains/families are created from common foundation/stock. The practical universality of the Color-Type Method was proved by the cattle industry many years ago (used to create new strains of cattle). Also used to create pure strains of lab animals such as mice, rabbits, rats etc... This method has been used to produce pure lines, consistent from generation to generation with a quantitative measurement of the inheritance of ability.
• Example: Rod Kershner began his strain of Bulldogs in 1989, from the best of Don Mayfield/Tudor's dogs. Today 14 years later the strain that they started over 100 year ago is still continuing at Rod Kershner's yard.
Kershner's Dogtown now just produced the fourth generation of some of the purest dogs alive.
The knowledge that Don Mayfield got from Earl Tudor, he passed on to Rod, and he
has been doing that for over fourteen years now. This blood has been highly respected
by most breeders around the world and you can find it in every Bulldog today, but not
many keep up the same high quality breeding.
His family of dogs is guaranteed quality, coming from some of the purest dogs of today.
His base is KERSHNER'S OR-NOT, who is not one, but the only Pure Blooded Mayfield dog alive. Owning a dog from Kershner's Dogtown it is like owning a part of history. (take a look at Kershner's dogs to see the Color-Type Method in action)
Genealogy rather than genetics – one should never use the Color-Type Method of breeding on the basis of genealogy alone. Many so-called breeders are caught-up in the breeding of pedigrees and not on the merit of the individual animals being bred together. Because certain lines/strains/families are more numerous and hence tend to produce more of exceptional class and various qualities ascribed to the different lines/strains/families responsible for successful dogs (and breeding programs) is precisely why the frequent recurrence of some individuals are in the pedigree of noted dogs. The pedigree breeder may sometime yield satisfactory results – but selection based on ancestry compares unfavorably with selection based on individual merits. While it is true, the pedigree is a blueprint of ancestry, one must place great reference on the individual merits and their capacity as athletes as well as producers before mating individuals regardless of their pedigrees, Many breeders today select prospective mates largely, if not primarily, on the basis of pedigrees only. Breeders should always start with the best possible gene pool; one must take care to choose the very best from that gene pool.
Breeding the foundation/stock – based upon a supposed optimum in the proportions in which lines/strains/families should be combined- a system “nick” or combination of bloodlines which already has produced exceptional dogs i.e.…Alligator/Jeep cross, Alligator/Eli cross, Jeep/Red Boy cross, Patricks/Jeep cross, etc…. One can use elementary principles of genetics to examine the ancestry of the dogs that made these combinations successful. This is where the pedigree becomes an important tool in ones breeding program-the biological handicap or genetic predication index. Examination of the ancestry, the individual, his parents, his sibs and half sibs, a pedigree at this point makes it more effective in predicting genetic probability and quantitative measurement of the inheritance of ability, especially when using the Color/Type Method.
Environmental Factors – after one is satisfied with the line/strain/family, one must keep in mind the environmental factor. The array of genes (genotype) may produce different characters if the individuals carrying them develop in different environments, “phenotype”- (the visible properties of an organism that are produced by interaction of the genotype and environment) the genes act as the regulator or modulators of this interplay. The range varies with the character under consideration and may in some cases be very wide, as in the case of size in which the same genotype may result in small size if some essential for requirements is withheld, or much greater size if all essential requirement for maximum growth are freely available. It is from such consideration that the general principles is derived which states that what is inherited is the potentiality of response during development to a range of environmental conditions (reasons some lines/strains/families change over a period of time/distance/location). Note: Sporting Dog Kennels, Inc. comparative data (data complied since 1975) from random bred and inbred lines, and from crosses between inbred lines, indicates the practical universality of heredity using the Color-Type Method of breeding.
One must reiterate, at this point, starting with the absolute best genetic gene pool is essential, for there are many individuals that have purchased dog (for the expressed purpose of breeding their own line/strain/family) that have magnificent pedigrees but are dumbfounded when they fail to produce any exceptional off-springs. One must keep in mind the hallmark of the American Pit Bull Terrier, his gameness, soundness and campaigning ability are the attributes most highly valued. It is these attributes that have kept this great breed pure and free from the importation of foreign blood (blood from other species of dog), genetic defects and precisely why using the Color-Type Method, one is still able to create new lines/strains/families, crosses and combinations that breed true. Note: Method developed and perfected by the Sporting Dog Kennels, Inc...
Sporting Dog Kennels, Inc.
Lawrance D. Mahomes
Last edited by sportingdog; 12-10-2010 at 04:20 PM. Reason: added something