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T Editor’s note: Here’s the latest on the Steynmere bobtail boxers from their breeder, Dr. Bruce Cattanach. For details on the beginnings of the bobtails, see the Oct. & Dec. ‘98 and the Feb. ‘99 issues of BU.

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Bobtail Boxers

by Dr. Bruce Cattanach, Steynmere Boxers, UK

Exciting things are happening in the bobtail Boxer project. Perhaps the least of these, which is still of note, is that we have moved through another generation. The first litter of the fifth generation Boxer backcross from the original Boxer x bobtail Corgi cross was born two weeks ago. There were eight pups, four bobs and four normal tails. Unfortunately, despite the bitch having an easy whelping of 10 pups in her previous litter, this time she needed a caesarian after taking two hours between the first two pups and then coming to a dead stop. One normal tailed pup and another with a bobtail were lost.

The bobtail parent of the cross was the big solid red dog I have been showing of late, Steynmere Hot Shot, and the dam was an older bitch of mine, Vonadel Twist And Shout of Steynmere, who was shown quite successfully as a youngster. The bitch is flashily marked, but no whites were expected or obtained in the litter, the dog being solid. There were three flashy and five solids (plains). Unfortunately, in the sense of looking for something to show in the continuing anti-solid climate, the two that were lost were flashy. So, the present score is two solid bob dogs and one bobtail bitch, and one flashy normal tailed bitch plus two other solids. Overall, a little bit disappointing as I needed bobtail bitches and the one bitch produced is not the best quality. Nevertheless, all look typically Boxer. One bobtail dog may be of some show potential and there are a couple with the normal tail type that look interesting. Actually the appearance of anything of show interest at all is quite intriguing as the bitch used does not have the best of heads. This was supposed to be a "production" litter rather than one for show quality. Show quality breeding may come later in the year with a couple of fourth generation bitches when, hopefully, I will have the option of a range of top stud dogs to use.

Bobtail 2

The most exciting news involves the scientific aspects of the study and comes in two parts. The first part concerns the bobtail gene itself. Colleagues in London whose interest is primarily in the genetics of human facial features have been eager to check out their candidate human "face" genes in an animal model. The Boxer and Corgi cross and backcrosses provided ideal material, the head types being so different, and the DNA for such a study was already there. But they had by chance also isolated another unknown DNA sequence. On checking the world gene database they found that this sequence had homology/similarity with a known mouse tail gene. They therefore offered to see if, by any remote chance, this gene might be responsible for the dog bobtail. Amazingly, given that there are many tail genes known in the mouse, it was. What a story: a human DNA sequence, a mouse tail gene, and now the same in the dog. Perhaps this illustrates why people like me are employed by Medical Research Council to work on mouse genetics.

Bobtail Boxers 3

From here on the study becomes "deep." The group has sequenced almost the whole way through the gene - identifying the order of the base pairs - and have found one base pair change that may constitute the mutation that causes the tail effect. Consistent with all of this has been the finding that throughout my four generations of crossing all the bobtail dogs were shown to have this variant form of the gene and all of the normal tailed dogs had the normal form. What is called functional analysis is now being performed, investigating the RNA and how it is expressed. And the two dead pups from the last litter, which have been held in a minus 80 degree freezer for the last two weeks, were taken up to the London group a few days ago for investigation. Studies on them may show if the gene brings about its effect in the dog in the same way as it does in the mouse, by affecting the inter-vertebral discs. This work and the findings made so far are considered so exciting that a publication is being rushed out. If the expression results can be obtained in time, a paper will be submitted for publication in one of the top international genetics journals.

"BINGO" for a "fun" dog breeding study.

The second part of this scientific investigation is of more immediate application and brings in the Norwegian Kennel Club with their two vets and their geneticist. They have been interested in the Corgi tail gene for some time. The vets have been searching for any associated ill effects, without success. The geneticist had planned to find the position of the gene on the dog gene map, but the new work in the UK has rather scooped this. Thus, because we now know what gene is involved and where it is located in the mouse gene map, we should be able to predict where it lies in the dog map. And the news of the moment is that the dog gene has just been located - in the appropriate position! Once again, this again shows the lack of boundaries in genetics.

But there is another critical question to be answered, and with the new results, this answer can be easily obtained. The question concerns the double-dose bobtail, the homozygote. And the question can be phrased in three ways. What happens when bobtail dogs are crossed together? What happens to the homozygote? Will the condition breed true?

Bobtail Boxer 4

To get the answers, bobtail intercrosses have to be done and a statistically defined numbers of the bobtail progeny have to be investigated. This would have been too demanding in terms of time, effort, and facilities for me to do alone, and it would even have been tough for a group of breeders, since every bobtail would have had to be test-mated. But now things are different. The Norwegian Corgi breeders have already done needed bobtail x bobtail matings. They have all the bobtail pups needed. And now, with the gene identified, test-matings are no longer required. Blood samples from the requisite number of dogs will be all that is needed to ascertain the presence or absence of homozygous double-dose bobtails.

Bobtail Boxer 5

The Norwegian-UK collaboration has started, and in a few weeks we will have the answers. But what then? If the homozygote is found and is normal in all respects other than the tail, the gene could validly, and without any perception of health risk, be available within the Boxer world and indeed, by the route of crossbreedinging, also to other customarily docked breeds. But, now knowing the mouse gene involved, I have to confess to pessimism. Maybe the Norwegians are convinced from the normal litter sizes and absence of abnormal pups in bobtail x bobtail matings that the homozygote will be produced and indistinguishable from heterozygous single-dose bobtail dogs, but the odds are that homozgous bobtail dogs will not be found. If correct, it would then have to be concluded that the homozygotes die early in development and include or replace the usual resorbtion losses that occur during pregnancy. They would then never be detected. The only observable consequence would then be that the bobtail condition would not breed true. Long tailed pups would be detected. The only observable consequence would then be that the bobtail condition would not breed true. Long tailed pups would always be produced in bobtail lines, just as whites are in current show lines. The frequency of longtailed pups would also be similar to that of whites in flashy show stock.

Bobtail 6

Would this scenario be an acceptable alternative to long tails in the event of an international ban on docking? I have some doubts about this, but perhaps I am jumping the gun. Let's get the answers first. I do hope that the Norwegians are right and that I will be proved wrong. The next bobtail report will be the critical one.

Bobtail Boxer 7
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