Speaking Heresy: A Dispassionate View of Cross-Breeding First published in Double Helix Network News by C.A. Sharp Several years ago the working Australian Shepherd community was rocked by a scandal. A breeder allegedly produced crossbred Aussies/Border Collies and registered them as purebred Australian Shepherds in order to gain an advantage in Australian Shepherd Club of America working trials. An act of fraud may have been committed – on the registry and on the trial system, but ASCA could do nothing to prove the case. By the time it became aware of the situation the parents of the alleged crossbreds were said to have died and thus could not submit to a blood test. The club’s board subsequently set up a DNA parentage verification program, one of the first by a purebred dog registry, as a step toward guaranteeing the integrity of its records in the future. Fraudulent registration and cheating in competitive programs is unacceptable and should be punished. The particular bit of fraud involved crossbreeding. But is crossbreeding in and of itself an evil? Closed registries of pure breeds, the norm in purebred dogs for many years, are a recent phenomenon in domestic animal breeding. Existing registries were set up within the past couple centuries and few, if any existed before that time. Prior to registries, pedigrees were not viewed as an essential part of breeding practice. Introduction of a totally unrelated animal wouldn’t be questioned if it produced desirable offspring. Eventually, registries were created so that the bloodlines would remain “pure”. At least in part reflecting social thinking of the times. The establishment of a reservoir of breed data – by way of pedigrees and whatever additional descriptive information was gathered – provided breeders with valuable reference material. Those knowledgeable in a breed could review a pedigree and have a good idea what lay behind an animal. Once sufficient dogs were enrolled, registries – and therefore breed gene pools – closed. Crossbreeding fell into disfavor, as the resulting offspring would not be eligible for registration. Today, people attempting to create new breeds may find themselves accused of “mongrelization” by breeders and fanciers of the parent stock. If a breed is numerous, descends from a large number of founders, and is not subject to much inbreeding, sufficient genetic diversity may exist to keep the population healthy. But if it is small in numbers or, however populous, has experienced a genetic bottleneck, the time may come when there is no place to go to breed away from its genetic weaknesses. Even a breed as numerous as the Australian Shepherd provides examples of such genetic constrictions. Aussies have three very distinct sub-populations, between which only minimal crossing occurs: The working lines, show lines and the Mini-Aussie. Dogs from each of these sub-populations might be registered with the Australian Shepherd Club of America as well as other organizations. The show dogs form the largest group and are mostly descended from dogs produced by the Flintridge kennel, which was active in the 1960s and ‘70s. The working lines are more varied in background but far fewer in number. The Minis, considered “undersized” by the standards of the breed as a whole, are comparatively few in number and descend from very few lines. The show-line Aussies and the Minis are experiencing difficulties with genetic defects. The inbreeding problem is less acute in the working lines, due to their greater diversity, but their small populations may at some point make it unavoidable. Show-line breeders have the option of out-crossing to a working line, if they can find a working breeder who is willing to cooperate. But the show breeder must be willing to accept the fact that the practice is unlikely to produce instance show-ring success. The Mini breeders are developing a separate breed. Recognizing that their gene pool was very restricted, the Miniature Australian Shepherd Club of America has formulated a plan to allow crossbreeding with Australian Shepherds. It is arguable whether this is true crossbreeding, since Aussies are the parent stock, but MASCA is giving its members an option for increasing genetic diversity in their breed. The MASCA program registers Aussies which are undersized by ASCA and AKC standards and puppies from Aussie/Mini litters. The dogs are given a special registration designation. The next generation will have a similar distinctive registration code. The following generation can attain the same registration status as dogs not resulting from crossbreeding or introduced individuals. These designations do not in any way penalize the dogs when it comes to competing in club-sponsored or sanctioned events. The program is very new, so it remains to be seen what extent Mini breeders take advantage of it. Working Aussie breeders face the biggest challenge. The Border Collie crossbreeding scandal is so recent that most are ill disposed toward the idea under any circumstances. But given their breeding goal – the preservation of the Aussie as a viable stockdog – they cannot readily turn to the rest of the breed for out-crosses. Herding behavior is genetically complex and dilutes rapidly if not deliberately maintained. While a fair number of show line Aussies might be able to pass a basic “herding instinct” test, they do not have the drive and highly –developed set of behaviors required in a true working situation. The only viable source of fresh genetic material that includes working behaviors lies outside the breed and beyond the pale for both the registries, and in their current mindset, the breeders. But, is crossbreeding really so unthinkable? Certainly, it is unworkable unless the registries allow it, as in MASCA’s program and those of a few other small registries and breed clubs (including the English Shepherd, another small-population herding breed). In other purebred species, some degree of crossbreeding is regular practice. The use of Thoroughbred crosses in racing Quarter Horse lines is an example. Crossbreeding has produced new breeds of market animals over the past few decades in response to changing consumer demands and husbandry practices. In dogs, closed registries and a ban on crossbreeding may be the rule, but the rule is not universal. Under the right circumstances, even major dog registries can accept crossbreeding. About fifteen years ago a researcher crossed a pointer with a Dalmatian and then back-crossed to Dals in subsequent generations. He successfully met his goal of eliminating inherited urinary problems that are present in almost every Dalmatian. The board of the breed club petitioned AKC to admit some of the products of this breeding program – dogs which had only one Pointer in a five-generation pedigree full of Dalmatians. Two of the dogs were admitted, but the breed club’s membership raised a hue and cry, voting to rescind the request. AKC refused any further registration of the “cross-bred” dogs. The membership of the breed club rejected these dogs because they were often mis-marked, allowing a cosmetic problem that might have been corrected in subsequent generations to take precedence over the elimination of a significant breed health problem. Another crossbreeding effort received a registry sanction – this time from the Kennel Club. The English registry is at least as conservative in its practices as the AKC. Another scientist wanted to create Boxers which did not need to have their tails docked. He crossbred to a Corgi. (The bobtail gene in Corgies is different from that in Aussies and does not produce serious defects.) After five generations he had Boxers that looked like Boxers and produced like Boxers but had naturally bobbed tails. Those dogs were allowed to be registered. If a crossbreeding program were to be developed, it would have to be open and aboveboard, sanctioned and regulated by the registries. The people involved with both the above examples never made any secret of what they were doing and why. If such a scheme were to be workable in Aussies, either to preserve working characteristics or to improve overall health and genetic diversity in the breed, only breeds or individuals which exhibit an acceptable phenotype (the observable behavior, temperament and appearance) should be considered. Where available, health screens should be required for recognized problems, which exist in either Aussies or the other breed. DNA parentage verification should be employed to guarantee that the crossbreedings are as represented. Some process, as seen in MASCA’s program, needs to be in place to record the breedings and eventually accept the descendants into full registration. Finally, breeders need to be educated on what to expect. Crossbreeding is not to be approached lightly, nor should anyone attempting it expect a rapid pay-off. Considerable research will be required. Does the other breed look and act sufficiently similar? Border Collies and English Shepherd are two breeds found in North America which might have something to offer. Other breeds might be located further afield – the Welsh Bobtail, German Coolie and Pyrenean Shepherd come to mind. No two breeds, however similar, are exactly alike. The Aussie breeder attempting to crossbreed needs to know what atypical traits the cross breeding is likely to introduce and how difficult they will be to select against in subsequent generations. For instance, if an Aussie is crossbred with a slick-coated breed, all the resulting puppies will be slick-coated. The trait is single-gene dominant. However if only coated individuals from the second-generation back-cross are selected for further breeding, the atypical slick coat will be eliminated. Multi-gene traits, on the other hand, will prove more difficult to weed out. To be truly effective from a health standpoint, a number of cross-breedings over several generations would need to occur. The challenge would be to maintain the original type in the process. Appearance traits can be recovered with comparative ease, even in extreme cases like the Boxer/Corgi cross. Behavioral traits may prove harder to fix but with time, patience, and careful study breeders can determine which traits tend to persist and which can be bred away from. Crossbreeding is not a panacea, nor something to be undertaken lightly. The practice must be open and accountable. With some purebred gene pools shrinking and other riddled with genetic problems, perhaps it is time for dog breeders to give consideration to that which as been considered heresy.