Continued from page 6
Bibliography
Animal Registration Officer, Establishment of a New Breed of Animals in Canada. Agriculture Canada. Ottawa, ON, Canada, 1991.
Bragg, J. Jeffrey, The Seppala Siberian: A Breeders Manual. 1976. Self-published. Vicksburg, MS. USA.
Bragg, J. Jeffrey, "C.K.C. Doesn't Know What to Do About New Siberia Import Dog." Siberian Husky Club of Canada Newsletter. March-April 1995.
Bragg, J. Jeffrey, The Canadian Kennel Clubs 1939 Siberian Husky Breed Foundation. 1996. Self-published. Whitehorse, YT.
Canadian Kennel Club, By-Laws, 1994, Etobicoke, ON.
Carson, Hampton L., "The Genetics of the Founder Effect," in Genetics and Conservation: A Reference for Managing Wild Animal and Plant Populations, Ed. Schonewald-Cox. Christine M., et al., 1983, The Benjamin/Cummings Publishing Company. Inc., Menlo Park. CA, USA.
Chambers, Steven M., "Genetic Principles for Managers," in Genetics and Conservation, Ed. Schonewald-Cox et al.
Chidiac-Storimans, Barbara, DVM, "Beating the System." Dogs in Canada, October 1995. p. 15.
de Boer, Shirley, and Ben de Boer, "How to Breed to Win -- Summary." Dogs in Canada, April 1994, pp. 30-31, 100.
Futuyama, Douglas J., Evolutionary Biology 2d Ed. 1986, Sinauer Associates, Inc., Sunderland, MA, USA.
Goodenough, Ursula, Genetics, 2d Ed. 1978, Holt, Rinehart & Winston, New York, NY, USA.
Hartl, Daniel L., and Andrew G. Clark. Principles of Population Genetics, 2d Ed. 1989. Sinauer Associates, Inc., Sunderland, MA, USA.
Lemonick, Michael D., "Flawed Beauty." Tlme, 12 December 1994. pp. 52-58.
Queens Printer for Canada, 1988, Ottawa, ON. 35-36-37 Elizabeth II, Chapter 13, An Act Respecting Animal Pedigree Associations.
Ralls, Katherine, and Jonathan Ballou, "Extinction: Lessons from Zoos," in Genetics and Conservation, Ed. Schonewald-Cox et al.
"Siberian Huskies Registered." Kennel and Bench, December 1939.
Templeton, Alan R., and Bruce Read, "The Elimination of Inbreeding Depression in a Captive Herd of Spekes Gazelle," in Genetics and Conservation, Ed. Schonewald-Cox et al.
Tudge, Colin. Last Animals at the Zoo 1992, Island Press, Washington. DC., USA.
Wachtel, Hellmuth, "The Evil Might of Hazard." Our Dogs, 21 April 1995. p. 12.
Weir, Mary Jane T., "Proposal Aims at Building Confidence in Purebred quality." Dogs in Canada, April 1994, pp. 25, 27.
Glossary
In the hope of helping the reader to understand certain genetic and other terms which may be unfamiliar, I have included this Glossary. It does not explain terms or concepts that have already been explained elsewhere in the brief, as for example, the concepts treated in the section headed "Lessons From Population Genetics." I have included here mostly terms which are technical enough to be omitted from most dictionaries. If the reader finds other unfamiliar words in the brief, their definitions will be found in any good collegiate dictionary.achondroplasia - a genetic syndrome producing skeletal development resulting in a semi-dwarf phenotype with shortened and distorted limbs; occurring in some breeds (Alaskan Malamutes. e.g.) as a genetic defect, it is selected for as a breed point in others (Basset Hound, e.g.).
allele - an alternative form of a given gene producing a difference in the trait controlled by that gene; some genes have only one allele, some have two, some have multiple alleles for the same trait.
allozyme - enzymes differing in electrophoretic mobility (i.e., which migrate different distances through the substrate when an electrophoresis test is performed) as a result of allelic differences in a single gene; allozyme variation thus indicates genetic variation. One of the oldest lab tests for genetic analysis.
autochthonous - "sprung from the earth," native to a particular region from a very early time. The Siberian sled dog is an autochthonous dog in Siberia. (Pronounced "aw-TOC-thun-us.")
chromosomes - structures within the nuclei of living cells which are made up of nucleotide sequences, the biochemical information carriers which we call genes. All genes exist as tiny portions of chromosomes; although we may speak of particular genes individually, in isolation, they do not exist as separate entities, but are always found as subunits of chromosomes.
cynological - of or pertaining to the knowledge and study of dogs.
deleterious · harmful or injurious.
diploid - the body cells of most complex animal organisms such as birds and mammals all have their chromosomes in pairs derived from sexual reproduction, such that one chromosome of a pair comes from the father, the other from the mother. The sex cells from only one parent have only half the number of chromosomes of cells in other parts of the body: the normal chromosome number is known as the diploid number, the chromosome number of sperm and egg cells is called the haploid number.
disequilibrium - imbalance or instability.
dominant - said of an allele which by itself alone will produce a particular phenotype regardless of which other allele may be present on the other matching chromosome of the diploid pair; thus it takes only one copy of the chromosome to cause a dominant trait to be expressed in the phenotype.
electrophoresis - one of the most useful lab techniques for revealing genetic variation. which came into widespread use in the 1960s. It involves placing sample material (blood, e.g.) on a gel substrate. An electrical field is then applied between the two ends of the substrate, causing protein molecules to migrate through the gel. Proteins with different ionic charge will travel different distances across the substrate. Staining subsequently makes bands of protein in the substrate visible, so that various samples can be "read" in much the same manner as a supermarket bar coded label.
expression - not all genes possessed by an organism will result in detectable physical traits or differences in that organism; the genes that do are expressed. Dominant genes are always expressed, but recessive genes may be present for many generations without physical expression in the phenotype.
fecundity - the number of progeny produced by animals when reproducing.
fertility - the relative degree of reproductive success, i.e. the frequency with which mating is followed by pregnancy.
gametes - the sex cells of sexually reproducing organisms, i.e. spermatozoa and ova.
genome - the total genetic information possessed by an individual, a breed or a species.
genotype - the invisible genetic makeup of an individual organism, which includes alleles which may be recessive and therefore have no visible physical expression.
heterotypic - displaying different types. A breed which has more than one distinct and recognizable set of "type" characteristics is heterotypic.
heterozygote - an organism that possesses different alleles at a given gene locus.
heterozygous - possessing different alleles at a given gene locus.
holistic - relating to or focussing on the entirety of a thing or an organism and the interrelationship of its component parts, instead of emphasizing different aspects or parts in isolation without considering their interactions.
homozygote - an organism that possesses identical alleles at a given gene locus.
homozygous - possessing identical alleles at a given gene locus.
inbreeding coefficient - a number used to quantify the probability that an organism will have identical alleles from the same ancestral source, usually computed by analyzing the pedigree for "loops" in which the same ancestor is found on both the male and female sides of a mating.
lethal - likely to cause or capable of causing the death of an organism. A lethal gene is one which could either cause an aborted fetus or the death of the organism at some later stage of its life.
locus (pl. loci) - the physical location of a given gene on a particular chromosome.
meiosis - the kind of cell division which produces spermatozoa and ova or gametes and which reduces the chromosome number to half the normal complement.
microsatellite - a kind of DNA testing which detects short DNA sequence variations at particular highly variable sites; used in so-called "DNA fingerprinting."
phenotypic - the visible physical expression of an individual organisms invisible genetic makeup.
polymorphism - difference or variation in form, diversity. Molecular geneticists study protein polymorphism, different forms of proteins in an organism indicating different alleles. Polymorphism studies show that from 20 to 50 percent of gene loci in most species have two or more allele forms.
recessive - a gene which contributes to the phenotype only if it is present in homozygous form. It takes two identical copies of a recessive gene to produce the trait it governs in the phenotype. In practice many genes are neither clearly dominant nor recessive, in which case geneticists speak of variable expressivity or incomplete penetrance.
RFLP - "restriction fragment length polymorphism" -- a DNA analysis technique which involves the use of enzymes to break the DNA chain at specific nucleotide sequences: the resulting "restriction fragments" are then analyzed by the use of electrophoresis and blotting techniques. RFLPs are used as markers for known genetic traits and can be employed for genome mapping.
sublethal - having known deleterious effects which by themselves will not usually cause the death of the organism but which handicap it in some way. Several sublethal genes may nevertheless combine to form a "lethal equivalent."
subvital - having known effects which work to reduce the overall vitality and health of the organism.
typology - the study of types or groups of distinguishing characteristics. Typological thinking involves emphasis on visible superficial characteristics, often mere cosmetic traits which have little to do with the health and viability of the animal possessing them.
viability - the relative survivorship of the fertilized ova resulting from a reproductive event. Nonviability may involve ova which simply fail to develop, fetuses which abort, nestlings which die or juveniles which fail to survive to maturity.
Afterword
The author most sincerely hopes that the foregoing brief has in one way or another stimulated or inspired your thinking about the breeding and selection of purebred dogs into the twenty-first century. Our fancy badly needs a responsible long-term perspective, both for our own good as breeders and for the good of our animals.If you should wish to comment on this brief, or if you should have some urgent unanswered question, the author will be happy to receive your letter at the address given below.
Should you feel indignant or upset after reading this brief, please put it aside for a few days, then read it again. I have introduced some ideas which, although they are becoming commonplace in other parts of the dog world, have largely failed as yet to reach Canada. Those who have accepted the gospel of breed purity inbreeding, and type above all, as published in a multitude of magazine articles and "how to breed" books, may well feel betrayed or insulted! It is not my wish to insult or to upset anyone, but I have nothing against disturbing complacency. We shall all have to rise above our own narrow individual interests and perspectives if we are to save our purebred dog world from genetic disaster.
If this brief -- as I hope it will -- leaves you feeling that The Canadian Kennel Club should be approaching the matter of genetic health in purebreds in a different way or should be considering new ideas, I hope that you will make your feelings clearly known to the Board of Directors by writing to the CKC Director for your region, whose name and address will be found on Page 2 of the "CKC Official Section" which is mailed every month to CKC members along with their copy of "DOGS in Canada."
In closing, I wish the best to all of us as we carry our breeding programs forward into the twenty-first century.
© Jeffrey Bragg, 1996
P.O. Box 4124, Whitehorse, Yukon Territory, Canada YlA 3S9Scanned into electronic form by Jolanta Jeanneney. Initial formatting and editing by Martin Vuille. HTML formatting by John Armstrong (jbarm@uottawa.ca).
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