To All Our Members

      This article is being published in the hope that our members can better understand the NRTA’s position on the existence of the Rat Terrier. It is intended to show the difference between the NRTA’s/NRTR's goals and practices vs other registries and organizations as educational material only.
The NRTA/NRTR exists for the Rat Terrier and not for individual personal gratification or short term gain. As an evolutionary association we will continue to make any necessary changes and do what is best for our breed. We are presently opposed to joining forces with AKC UKC or any registry that doesn’t have the best interest of the breed in mind. We at the NRTA well understand what has happened to breeds that have become a part of these organizations. We hope that by reading this article you will have a better understanding but ultimately it is your own individual choice to which way you want to go.

     Parts of this article are very technical reading but in the scheme of things are very important. There is a glossary at the end to help you understand some of the terms. Take your time reading, it is well worth the effort.
 

Purebred Dogs
Reprinted with permission from the author

What is a Canine Breed?

      What is a breed? To put the question more precisely, what are the necessary conditions that enable us to say with conviction, "this group of animals constitutes a distinct breed?"  In order for canine breeds to fulfill their destinies effectively, the three distinct axes along which breeds are distinguished must have equal importance and consideration, otherwise serious problems arise. Breeds cannot be distinguished by ancestry alone, by purpose alone, or by type alone. Unless these three vectors of breed identity interrelate fully and cooperatively, the fullness of that identity is missing or marred. Unfortunately, this full and cooperative interrelationship is a rarity in our contemporary dog world. The criteria of ancestry are applied rigidly and mechanically; the criteria of purpose and utility are subordinated or not considered at all; the criteria of type are applied in a highly exaggerated, obsessive fashion. The interaction of the three approaches is seldom considered and almost never is a sustained effort made at the integration of the three.
The Origins of Dog Breeds

       It must be realized that canine breeds are manmade, created by artificial election out of the endless diversity of the canine gene pool.

      An important characteristic of breeds is that they are created by breeders -- not by registries or protective organizations such as The American Kennel Club. The origin and course of a canine breed is in the hands of its breeders, first, last and always. It is the business of the biologists who study the formation, structure and function of cells and support the work of dog breeders and not vice versa.  All else is secondary.

      Ordinarily a breed has already existed for an appreciable length of time before it reaches the point of becoming a recognized breed served by a registry. Nonetheless, the event of its "recognition" by a registry such as AKC is always a crucial one in the history of a breed. As things now stand, breed recognition is far more crucial (and ultimately damaging to the welfare of the animals) than it need be or ought to be.

The Healthy Continuation of Breeds

      Purebred dog Dom is even now in serious trouble through a general failure to distinguish between what is necessary to establish a breed and what is desirable to continue that breed in perpetuity. Most registered   breeds are less than a century old as registered breeds; many are but fifty or sixty years old. Yet nearly all   breeds now show levels of expression of genetic defects that must be considered unacceptable. Over 500
distinct genetic defects have been cataloged in various breeds of purebred dogs and more continue to come to light regularly. Some of these have reached very high levels of incidence, creating problems for breeders and dog owners, threatening the health of entire breed populations. What is worse, in many instances organized control programs seem relatively ineffective. Although such programs successfully identify affected animals, in some cases individuals with several generations of "clear" ancestry stubbornly continue to produce affected stock.

The Fallacy of Breed Purity

      The present structure of The American Kennel Clubs studbook registry (and others like it) embodies a fallacy which is directly responsible for the current genetic crisis in purebred dogs: the fallacy of breed purity. The ideal of the purified lineage is seen as an end in itself; accordingly, the studbook has been structured to reflect and to enforce that ideal rigidly and absolutely. The idea of the superior strain was that by "breeding the best to the best," employing sustained inbreeding and selection for "superior" qualities, one would develop a bloodline superior in every way to the unrefined, base stock which was the best that nature could produce. Naturally the purified line must then be preserved from dilution and degradation by base-born stock. There is no support for this kind of racism in the findings of modern genetics -- in fact, quite the opposite: population groups that are numerically limited and closed to new genetic inflow are now thought practically certain to be genetically inferior.

      Population geneticists insist that limited populations under strong artificial selection, subjected to high levels of incest breeding - such as the AKC purebreds -- simply cannot maintain genetic viability and vigor in the long term without the periodic introduction of new and unrelated genetic material. They are referring, moreover, to true out crossing, the introduction of stock unrelated to the breeding line, not merely the use of a dog which might be from someone else's kennel but is derived from exactly the same foundation stock some generations back.

The Demise of Typo logical Thinking

      The fanatical pursuit of breed type to the exclusion of other more important factors (more important to the dog, to his owner, and to his veterinarian) has led to a distinctly unhealthy situation in most breeds. Since the majority of breeders within AKC seem to direct their efforts toward the production of a winning exhibition specimen, and since many breeders therefore breed their females to the males that do the most winning at dog shows, a situation has arisen in which continued effort to produce show winners leads consistently to greater and greater exaggerations of "type", that being the factor most susceptible to the off-the-cuff three minute analysis of the breed ring. It is an accepted fact that strong incest breeding is the fastest route to this kind of "success".

      The show ring has also been largely responsible for the decline of breed purpose, working ability and
temperament in a great many breeds, notably sporting breeds, herding breeds and sled dog breeds. The quick and easy gratification of blue ribbons and gilt trophies all too readily supplants the hard work necessary to preserve and advance canine working abilities. If our dog breeds are to conform to the ideal of "a sound mind in   a sound body" , the fancy must find some way of ensuring that less dog breeding takes place along the lines of least resistance and cheap gratification, so that greater attention is paid to working characteristics, temperament and trainability. A balanced outlook on breed identity must be restored by integrating canine function with the ideals of conformation, beauty and "type." All kinds of dogs, toy breeds not excepted, can perform useful functions and respond to training. Those aspects of the fancy should be accorded an importance at least fully equal to that of type and conformation instead of being regarded as merely optional. For example, breeding and exhibition of utility breeds such as gun dogs and sled dogs merely for sale as pets and for dog shows, with no effort made to maintain and advance their working capabilities, is an obvious abuse which must lead inevitably to mental and physical degeneracy in those breeds.

Abandoning Natural Selection

      The breeder of domestic stock often assumes that he has abandoned the realm of natural selection and that only artificial selection plays a significant role in his breeding program. Nothing could be further from the truth. The breeder may attempt to abandon natural selection; natural selection, however, will not abandon his stock.

      In our quest for breed purity, the superior strain, and classic type, we have made a sad mess of our dogs - with unhappy, neurotic temperaments, epilepsy, blindness, deafness, immune system weakness, skin diseases, blood disorders, endocrine system malfunctions, crippling blood disorders, deliberate deformity, and often even the inability to reproduce their kind without breeder and veterinary intervention. How clever we have been!

      Can we not now take a clear-sighted view as the millennium turns slowly over, of what we have done - of our own pitifully flawed creation in our world of purebred dogs and, like mature, intelligent people, clear away the mess and try to do better? Can we not learn from bad experience? If we would be truly clever, we might attempt to imitate more closely the methods of nature, to work within the natural system, instead of for our own ends. That would indeed be clever. I think that that is now possible, if we would but step outside our own incestuous little purebred world and learn something of what people working in other zoological fields of endeavor have already learnt.

A Century of Nineteenth Century Dog Breeding

      How, then, may we set about correcting the accumulated errors of over a century of what we might call
nineteenth century dog breeding? First of all it might be wise to attempt a short list cataloguing the errors and abuses of which we are aware, the areas known to be deficient in one way or another.

      * Dog shows must come high on the error list. They began as an arena for the evaluation of breeding stock, they continued in the form of the "bench show" as a public showcase for purebred dogs. Both functions are now ill served if not virtually abandoned. Championship shows are now just that, mills for the production of Champions, Best in Show and Group winners, little more. They contribute almost nothing to the true welfare of dog breeds; they have few lasting positive values to offer breeders, only temporary fads and fashions.

      * Breed purpose and the cultivation of canine utility have a low status in the fancy compared to what one author called the glitz and hype of the show world. Those who concern themselves with the working ability of their dogs exist mostly in ghettos where little communication takes place with other branches of the fancy where shows are going on.

      * Obedience work, begun as a way of initiating dog owners into the fascination and technique of training one's pet to be a pleasant, well behaved companion, has become largely ritualized and sterile. The pursuit of "Club 200" (the perfect point score) has become an obsession. Intelligent and useful training on the owner's part, intelligent obedience on the dog's part, are now beside the point. What matters all too frequently now is the minutely perfect performance of a set ritual. Here again we find a canine ghetto.

      * The worship and exaggeration of type, as already noted, is responsible for a multitude of ills.

      * Modern registries based on a rigidly closed studbook are throttling the genetic health of all registered dog breeds. Genetic misery is now a real and present threat. Many breeds now bear a genetic load of   defects which has grown totally unmanageable as their respective gene pools have become more and narrower through thoughtless breeding and selection practices.

      * Incest breeding, once a convenient tool for the rapid fixation of type in newly registered breeds, has become virtually standard practice for those who seek success in dog breeding. The net effect has been the decimation of gene pools, widespread homozygosis and the unintended fixation of unknown scores, hundreds or thousands of genes, many of which are proving to be harmful or lethal to the animals that bear them.

      * The AKC, born in the height of the Victorian era, seems to cling to cumbersome structures, making it difficult for the Club to respond in a timely fashion to external challenges or internal needs. The entire By-Law and Amendment structure could do with modernization. One feels a general atmosphere within the Club of restrictedness and ultra conservatism, as if those in power felt that only they themselves, the "old hands," knew what is good for purebred dogs and the fancy, and that newer members should not be entrusted with the franchise.

      * Breed clubs seem to possess little real power to represent breeders or their breeds effectively. Special measures which they may feel essential for the health, development, and protection of the breeds whose breeders they represent must be put through the centralist AKC system and approved by the Board before they become effective; often such measures have little chance of approval because they are felt to conflict with the rigid all breed norms of the Club. Since breed clubs have relatively little real power, they often tend to be less than fully representative of all breeders of a particular breed. Frequently they are more or less run by cliques; they waste much time and effort in wrangling and personalities, being perhaps inadequately supervised and not taken terribly seriously.

      * Breeders, as well, are sometimes far from free to make their own responsible decisions for the best interests of their own dogs and bloodlines being closely constrained by AKC Bylaws. Little discretion is given them regarding matters such as delaying registration of stock until it reaches physical maturity, the introduction of new genetic material when in their judgment it is needed for genetic health, etc.

      Many of the abuses and deficiencies not rooted in outmoded attitudes such as racism and elitism arise from misunderstandings of genetic realities. Let us now examine briefly a few points of up-to-date genetic theory as they relate to purebred dog populations.

Lessons from Population Genetics

Gene Frequencies

      Much of the work of population genetics involves estimating or calculating gene frequencies, which quantify the relative commonness or scarcity, within a particular population, of alleles at a particular gene locus. If there is only one version of a gene in the population, then the entire population is necessarily homozygous for that gene. Gene frequencies are expressed as decimal fractions which must add up to unity, so a gene without alternative alleles has a frequency of 1.0. The gene frequency figure is a ratio of the number of copies of alternate versions of a gene in the population, independent of the number of animals involved and of whether they have the gene in homozygous or heterozygous form. An individual may have two copies of the same allele or it may have one or none. For example, if a locus has two alleles, and the population involved consists of fifty animals, and there are 25 copies of one allele, then the frequency for that allele is 0.25; therefore the frequency of the other allele must be 0.75, with 75 copies of it in the same population. It must be emphasized that gene frequency by itself says nothing about relative heterozygosity or homozygosis; it deals only with quantitative aspects of alleles in the population, not the diploid genotype of individuals.

Founder Events

      Perhaps the most crucial concept in population genetics for dog breeders is the founder event, for its theory describes perfectly what takes place when a breed is "recognized" by AKC or a similar registry. Whatever may be the state of genetic balance or the frequency with which particular genes are found in the general canine population, it all changes when a founder event occurs. In nature such events happen when individuals of a species occupy and reproduce in territory new to the species, losing contact with the source population of the migrants (as when small birds are deposited by hurricane winds on mid ocean islands). The founder event describes the establishing of a small population, although later on it may grow to be a large one. When a finite number of individuals found a new population group, the genome of the new group will necessarily reflect the genes brought to it by the founder animals; gene frequencies within that population will reflect the gene frequencies within the founder group rather than that of the source population.

 In this way, when a founder event occurs, a gene quite rare in the source population may have a much higher frequency in the new population; conversely, genes common in the source population may be infrequent or even absent from the new population. It all depends on the genes of the founders! Thus a genetic defect extremely rare in the overall canine population can come to be common in a particular breed simply because one or more individuals of a small breed foundation carried that gene.

Genetic Drift

      Small populations, such as most purebred dog breeds, are subject to a condition known as genetic drift. This is a situation in which gene frequencies change at random from generation to generation, varying from statistical expectations because of sampling error. (Sampling error occurs when too small a number of trials departs from the expectations of probability, as when someone flips a coin six times and gets five heads and one tail - if he flipped it 600 times, the results would be close to 300 heads, 300 tails, but in a small sample, chance can cause a departure from the expected result.) A dominant black dog, whose dam was white, when bred to a white bitch should in theory produce equal numbers of white and black pups, but few breeders would be very surprised to see 2 whites and 6 blacks, or vice versa. Yet when such sampling errors occur in small populations, over subsequent generations gene frequencies can change, taking a random walk that leads finally to the loss of one allele and the fixation of the other! The smaller the population, the fewer generations this result is likely to take. In a very large population, it will not happen at all. Genes are lost and other genes fixed completely at random in this way by genetic drift.

Generation Time

      Since in limited, genetically isolated populations such as AKC breeds a certain amount of genetic diversity is lost with each reproductive event through the action of genetic drift, inbreeding and artificial selection. The number of generations from the founder event becomes an issue. The average time between one generation and the next is a convenient yardstick to help us realize the relative rate of genetically slow destruction. A few instances exist in which certain bloodlines - working dogs, usually - are bred conservatively enough that the generation time is as much as an average six or seven years.

      But this appears to be exceptional. Many exhibition lines seem to operate on the following model: "Phoo-Phoo" starts his show career at six months of age in Junior Puppy class, is heavily "campaigned" and has all his Championship points by ten months of age. The owners' immediate "bragging ad" in "DOG World" or the breed club newsletter recounts his triumph, adding that "puppies from Ch. (subject to AKC confirmation) Phoo-Phoo are eagerly awaited next month". In such lines the average generation time may be two years or even less. This reproductive rush has two implications: first, a greatly accelerated rate of loss of genetic diversity; second, an implicit selection for early maturity which carries with it an elevated risk of joint disease and a lowering of average longevity.

Effective Breeding Population

      Anything that limits the number of males in use drastically restricts the effective breeding population. Overuse of popular sires is a tremendous factor in the genetic impoverishment of purebred dogs. One of the major drawbacks of the AKC Foundation Registry is the virtual certainty that the existence and promotion of a few "elite" sires, titled, temperament tested and certified "clear" of major hereditary diseases, will further dramatically reduce the effective breeding population in many breeds, causing further declines in breed vitality and viability and leading to the loss of vitally needed breeding lines which happen not to be among the elite group.

Assortative Mating

      Assortative mating is a method of selective breeding capable of creating homozygosity for desired traits without having as great an effect on overall homozygosity as does inbreeding. It consists of mating pheno typically similar individuals that are not closely related. This method of selective breeding would be capable of maintaining a reasonable range of breed type in a balanced heterozygosis breed system with an open studbook.

The Crux of the Problem

       The one problem which most concerns the entire purebred dog fancy is genetic defects. Breeders used to worry about overshot/undershot bite and cryptorchidism. Not much else of a genetic nature was cause for concern; fanciers were a lot more worried about distemper, hepatitis and internal parasites. Breeding programs concentrated on individuals' visions of canine excellence.

 Then in the 1960s the tip of the genetic iceberg emerged as concern grew about a joint disorder called hip dysplasia. A control program involving the examination of hip x-rays by a skilled scrutinizer and the maintenance of a registry of animals "cleared" of the defect was established at the Ontario Veterinary College at Guelph, Ontario. Now after four decades of the OVC program it has been pretty well established that "clear" animals with several generations of "clear" ancestry can nonetheless produce dysplastic progeny. Hence the OVC control program would seem to be of questionable effectiveness. The OFA program in the United States has these same issues.

 As the generations of closed studbook breeding have advanced, many other inherited problems have emerged in purebred dog breeds. There is no need to list them here; the list would be on its way to obsolescence in a month or so; veterinary research continues to define more inherited disorders regularly. Many breeders now run four way screening programs; some may screen for even more problems. Yet thirty years of x-rays have not eliminated hip dysplasia - it is now widespread in breeds in which it was not a problem thirty years ago.

      Several years ago Time magazine published a scathing indictment of the American Kennel Club and of purebred dogs and their breeders, targeting in a cover story the problem of genetic ills, suggesting that the best use of pedigree papers was for housebreaking the puppies and recommending that the public satisfy its desire for canine companionship with mongrels. Since then, most of us have known we have a situation that is on shaky ground on our hands. Our reputation as breeders of purebreds is now in tatters; we are caricatured in the media as greedy, uncaring producers of degenerate animals.

      It is time for us as dog breeders to stand up for ourselves and for our dogs, to reject the accusation that we ourselves are individually to blame for the problem of genetic defects, and to demand swift remedial action by the Club. The crux of the problem is the closed studbook and with it, the ideal of breed purity, the worship of type and the preeminence of the championship show as goal and arbiter of most breeding programs.  Armed  with the concepts of population genetics, we can now examine the last century of dog breeding, ascertain what has gone wrong, and establish ways and means to correct the situation.

We stated that the recognition of a breed by a registry was a crucial event in its history, more
crucial than it need be. That is because the usual practice has been to open the registry to foundation
stock for a limited period, to inspect and register a small population of foundation animals, and then
to close the registry to new genetic inflow forever after, with the sole exception of animals of the
same breed imported from other registries and derived from the same or closely related foundation
stock. In recent decades there has usually been no unique AKC foundation stock except in the case of
native breeds; AKC merely accepts registered stock from other jurisdictions. Most of the breeds we are familiar with were founded from sixty to over one hundred years ago.

      The canine species possesses tremendous genetic diversity as a whole. Like most species, that diversity includes a genetic load, a wide variety of more or less harmful genes, probably quite a few of them held in a state of heterozygote superiority, so that although natural selection tends to eliminate homozygote recessives when they segregate, the bad genes themselves maintain a strong presence due to the selective advantage of the superior heterozygote.

An Example from One Breed

      The recognition of a breed creates a founder event when the registry is opened; a limited number of breed foundation animals are selected, often from a population which has already undergone considerable inbreeding and selection. Let us take for an example the Siberian Husky breed. Registered in 1939, the initial AKC population consisted of 47 animals, all belonging to or bred by one kennel! Of those 47, nine were foundation stock of the kennel whose dogs were registered. Two of those were males imported from Siberia - literate brothers! The other seven were mostly related to one another. (Two were seven eighths Siberian and one eighth Malamute.) The other thirty eight were all progeny and grand progeny of the founders. Of the nine foundation progeny contributed to further breeding. Of the two Siberia import males, one brother was always bred to the same bitch, producing a large number of progeny of identical pedigree; the other brother was usually bred to daughters of the first brother.

 Today Siberian Husky lines that trace directly back to the Canadian foundation stock owe 25% of their pedigree lines to the first brother, 15% to the second brother, and 27% to the first brother's invariable mate! Two thirds of the genetic heritage of these modern Siberian Huskies derives from only three foundation animals! This is not an exceptional situation; it is a fair example of the early breeding history of AKC breeds.

      In the case of the Siberian Husky, then, (which happens to be my breed, with whose early history I am reasonably well familiar), The American Kennel Club opened a registry in 1939, inspected one kennel's dogs and admitted four dozen closely related individuals to the registry, which was then closed permanently. No effort was made to ensure a broad foundation, nor a numerous one, nor a genetically diverse one.

      Just how permanently the registry was closed I recently found out when I imported from Russia a dog bred to the Siberian Husky standard! The dog was born in the Ural Mountains well within the boundaries of Siberia from parents of Chukotkan village origins; he had three generations of known ancestry (without registration numbers since there is no official "Siberian Husky" registry in Russia). I was immediately told that the Club "did not know what to do" about my application to register the dog, that the protocols used to register breed foundation animals in 1939 were no longer valid, and that my dog "should not be used for breeding because it would probably be a long process," in spite of the fact that the dog had a valid FCI Export Pedigree from the Czech Republic (through which he was exported). A year and a half later after repeated in camera discussions, the import was refused recognition by the Board and Registration Committee on grounds of inadequate information (no ancestral registration numbers). Repeated calls for Club inspection of the import and offers to submit the animal to DNA tests and progeny testing were ignored. The registry is closed - even to new Siberia imports!

      For the past 63 years, then, all Siberian Huskies bred in American have stemmed from the 1939 registrations, or from Canada imports, which mostly stem from the same dogs AKC registered, plus perhaps three additional animals. The original foundation animals were poorly utilized and subsequent generations were so closely inbred that the two Siberia import males plus one bitch are even today still statistically equivalent to grandparents of every single Siberian now registered!

      Thus the original founder event in my breed plus the closed studbook has resulted in a state of forced inbreeding for Siberian Huskies. Thirty generations of breeding all going back to ten dogs or fewer represents an impressive feat of sustained inbreeding! Predictably enough Siberian Huskies, which eighty five years ago were probably the toughest, hardiest variety of dogs on earth, now suffer from the same gamut of genetic defects that afflicts other breeds. Few if any registered Siberians are now able to perform as sled dogs. There are many other breeds that met this same fate.

The Holistic Breed

      Now I would like to evoke a vision of the future -- but not the distant future. I want to describe how dog
breeds might be in the twenty first century. Instead of all breeds being subjected to arbitrary structures not
equally well suited to them all, each breed would get whatever special measures its breeders thought necessary. Instead of a fragmented canine fancy with ghettos of show, fanciers, obedience buffs, and working dog specialists, dog breeds would have the benefit of a holistic outlook, integrating the various aspects of canine: activity and producing well rounded, versatile, mentally stable animals.

      The notion that genetic disease can be controlled, much less eliminated, by screening programs and selection has not been borne out by general experience. Those who promote such a notion are engaging in a cruel, self serving deception. It may be that a breeder can sometimes improve his odds against producing defective stock in a given mating by screening the parents, but experience has proved that screening will not solve our genetic problems in any wider sense. Despite generation after generation of "clear" stock, bloodlines can still produce more and more affected animals. That is because our problems are inherent in the closed studbook/incest breeding system. In order to restore genetic health we shall have to adopt a different system.

       Genetic defects are not "eliminated" in nature. Instead random mating and behavior patterns that discourage inbreeding take care of the problem by ensuring high levels of heterozygosity and the consequent rarity of defective homozygote. If we take steps to set up similar patterns in purebred dogs, we shall be able to reduce the level of expression of defective genes greatly, which is all that is required. The end in view is healthy stock, not "racial purity."

      Many breeders will reject outright the mere idea of deliberately trying to increase heterozygosity, after so many years in the pursuit of homozygosis through "line breeding" and frank incest breeding. Others will be horrified by the thought of dismantling the apparatus of the AKC Championship Show. The genetic situation is dire and the present outlook for many breeds is grave. Something will have to be done. Just now most of the hope and effort rests upon research towards detection of DNA markers for major genetic diseases. Yet those who promote this approach to the problem of genetic defects invariably seem to have a very narrow outlook, treating each defect in isolation. The approach is no different from that of traditional hip x-rays and eye examinations, except that it may be more efficient. The proponents of disease marker detection do not, however, explain how we are going to deal with the problem of diseases which are already widespread throughout a breeds population, or how our gene pools will stand up to successive waves of severe culling as we strive to "eliminate" one widespread genetic disease after another in our small populations bred from tiny founder groups.

      What is of paramount importance is that we all recognize the true dimensions and gravity of the problems we now face. It is far too easy to ignore genetic diseases, to make excuses, to pay the vet bills and say nothing for fear that others will accuse one of breeding defective stock -- I think practically all of us live in fear of the smear tactics that are so common in the dog world. Yet the truth is that we are all breeding defective stock; the system itself virtually guarantees that. If we believe that to breed defective stock is a bad thing, then we simply must discuss ways and means of altering that system to allow us to restore genetic health. Too many breeders are now reluctantly deciding that "health must be the paramount concern" and abandoning their usual selection criteria in favor of breeding for hips, eyes, blood, etc. A few decades of that sort of breeding will surely do greater harm to breed characteristics than could ever be done by outcrossing. We must now seek to evolve a system which will naturally, almost automatically, produce healthy animals -- so that we may continue on with, or return to, our selection for temperament, working ability, conformation and breed type. Most of all, it is imperative that we start now to discuss and work on the new structures that are needed to facilitate genetic health for our dogs but it may be too late.

Glossary
 I have included here mostly terms which are technical enough to be omitted from most dictionaries.