CHART
© 1970 by Mrs Joan Beard

As printed in the A.S.C. Asian Breeds Bulletin (NSW, Australia) May 1970 pages 4 & 5.

Apso breeders will be welcome news received by Mrs. Joan Beard in connection with the
“Prapso” problem (untypical smooth-coated and smooth muzzled specimens that occasionally occur in otherwise normal litters).

Information about the pedigrees of “Prapsos” was supplied by Apso breeders in Australia and the U.K. and submitted by Mrs. Beard to CHART, an organisation which specializes in the charting of pedigrees for a subsequent study by geneticists.

It now appears to be generally agreed that the inheritance pattern of “Prapsos” is not a simple dominant/recessive relationship as was first suspected, but involves what is called QUANTITATIVE CHARACTERISTICS.

Quantitative inheritance involves characterists  which depend on the interaction of a very large number of genes, all able to effect each other in varying degrees. This type of inheritance is extremely complex. However, despite its complexity, it is within the powers of the average dog breeder who has not a deep knowledge of genetics to deal with the situation by strict adherence to the classic rules of good dog breeding methods.

One encouraging aspect is that good specimens of the breed, that have produced “Prapsos” do not need to be completely written out of a breeding programme, as would be the case if the cause were straightforward dominant/recessive relationship, but may be used to a limited degree.

The following is a suggested policy for breeders to follow:

  1. Obtain as much information as possible about the animals appearing in the pedigree of individual stock. This means the qualities of each animal, its ancestors and descendents, the characteristics typical of the breeding lines involved. This will frequently involve co-operation between breeders and the exchange of information. Special care should be taken when using dogs close to imports without pedigrees. (Anyone wanting information about early stock in Australia should contact Mrs. Beard, and for information about the U.K. lines, contact Mrs. Frances Sefton.)

  2. Keep complete records of all stock, of each mating and the resulting litters. This should include a chronological record of the development of teeth, coat and growth. Records make it possible to obtain a picture of the standard of quality being obtained, and the progress being made, which can then be compared with the Breed Standard, and with other breeders’ achievements.

  1. The aim should be to reduce the number of untypical specimens occurring in the breed over all and reduce the variation from the Breed Standard in one’s own breeding strain. Again, co-operation and the exchange of information is essential.

  2. Try to find, if necessary, by trial and error, combinations which “nick”. “Nicking” is the term used to describe a mating between animals which produces progeny nearer to the Breed Standard and better in quality than other matings. The genetic makeup of one strain frequently complements some better than others. There is no point in continuing to repeat matings which produce disappointing results.

  3. Use strict selection of breeding stock. Keep and use only the best. Sub-standard stock will do nothing to improve the progress of the breed.

  4. While aiming for true type, general soundness must also be remembered, so selection should be based on animals sound in mind and body.

  5. Environment frequently affects the very characteristics that are governed by heredity. Good husbandry is essential. Good feeding is needed for correct teeth development, bone and correct growth, but the diet should be well-balanced, neither lacking in essential nutrients or nor overloaded with supplements so that the delicate balance is disturbed. Coat care depends as much on care as on heredity.

Anyone who is interested to know more about Quantitative Genetics will find “Genetics of the Dog” by Marca Burns and Margaret N. Fraser (Commonwealth Agricultural Bureau) useful, particularly Chapter 12. There are also more advanced books on the subject referred to in the bibliography of this book.

 

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