06.11.2010

The inheritance of smooth and longhair in the Havanese breed.By mrs. Karin Biala-Gauss (Copyright 1997) (Germany/Deutschland)Translated by mrs. Catherine Marley (USA) and Dr. Inge Friedrich (Germany)All photos are made by/copyrightGermany

SMOOTH COATED SHIH TZUS

Smooth COATED Lowchen

Smooth COATED Lhasa Apsos

Beginning about two years ago, Havanese breeders have been finding "smooth: puppies in their litters. This is, of course, not only a German problem, but our system of breeding control makes it impossible to sweep such matters "under the rug".

Inquiries in neighboring countries, (who have quite the same bloodlines as in Germany) received the answer that "This has never happened to  us!" We have always treated this phenomenon with complete candor here in  Germany, and we hope that now breeders in other countries will begin to lose  their inhibitions and be more forthcoming.

he first smooth-coat Havanese "struck us" in the mid 80's, but they were so rare that they did not attract much attention. For many years, Havanese breeding continued without incident until in 1995 there was a sudden rash of smooth-coats appearing in several different kennels.

The smooth-coat puppy is unremarkable at birth, the first signs  appearing on the hair of the extremities. Experienced breeders can first recognize the smooth-coat in puppies as young as 5 weeks, as the body hair is  more fluffy than the hair on the legs and face.

We suspected a simple recessive inheritance. Since we could obtain no information from other countries, the Association, after consultation with Mr. Eberhardt, the VDH breeding director, decided to do a test mating to confirm this assumption. Our plan to mate two unrelated smooth-coated Havenese was torpedoed  when the male's owner refused to let us use him. Therefore, two smooth Havanese were selected, which had the same grandsire - a dog appearing in the ancestry of recent smooth indivi

Mrs. Ursula Geipel volunteered to raise the pups. Since breeder was willing to put their kennel name on such a test litter, the litter was named "VK Experiment". It was understood from the beginning, that none of the progeny would be registered for further breeding, no matter what their coat type. As was expected for a recessive mode of inheritance, all four of the resulting litter were smooth-coats! Although one breeding is not enough for scientific proof , we believe this result is sufficient to strongly suggest a simple recessive mode of inheritance

For all those who may not be familiar with the genetic aspects of  dog breeding, here is a brief explanation of the inheritance  pattern:

For each trait that is transmitted through a simple recessive/dominant manner, there is a single gene-pair responsible (in contrast to the polygenetic modality in which  there are several different genes at different locations which combine to cause the trait). This gene-pair is composed of two single genes, one from the father, and one from the mother. The name given to the gene-pair which causes the expression of a trait, is "alleles".

The  expression of an allele is not necessarily strong. For example, a dog which has inherited a gene for short hair from his father and a gene for longhair from his mother, will not have an intermediate hair length, but is either short OR long haired. One of the genes must be stronger than the other or "dominant". The weaker gene is termed "recessive". To express this relationship and behavior in  genetic formula language, the dominant gene is indicated by block capital letters, while the recessive is indicated in lower case letters.

n the simple dominant / recessive schema, there are three  possible combinations, that the individual dog can inherit: 1.He is "homozygous  dominant" , i.e. he has a dominant allele from each of his parents, and consequently shows the trait that the dominant allele can cause. 2.He is "homozygous recessive", i.e. he has a recessive gene from each parent, and consequently shows the trait which the recessive allele can cause. 3.He is mixed, or heterozygous, i.e. he has a different allele from each parent, and will show the trait caused by the dominant allele.

It should be obvious, then, that two animals homozygously (doubly) recessive for a trait will ALWAYS breed true because there is no dominant to  oppose it.

Looking now at the Havanese coat question, we propose that there are alleles for the coat length (long-hair and short-hair), in which the allele for short coat is recessive and the allele for long-coat is dominant.. Thus we have three possible genotypes for Havanese coat, but only two possible "phenotypes" (visible coat types). 1.Homozygous long-hair, thus both Alleles dominant, which we will designate as LL. 2.Homozygous short-hair, thus both Alleles recessive, which we will designate as kk 3.Heterogygous [Mixed], thus a dominant allele for long-hair = L and a recessive allele for short- hair = k, so that the resulting Lk, appears to the eye (phenotype) to be longhaired, but  which carries the hidden allele for short-hair, and can produce a short-haired offspring when mated to an appropriate partner which also carries the k allele.

If we  breed Havanese now, there are six breeding outcomes theoretically possible. 1.Homozygous long-hair with Homozygous long-hair [LL] x [LL]Possible combinations: [LL LL LL LL] Results in to 100% Homozygous long-haired  Havanese2.Homozygous short-hair with Homozygous short-hair [kk] x [kk]

Possible combinations: [kk kk kk kk]

Results  in to 100% Homozygous short-haired Havanese. (This was our  attempt-mating.)

3.Homozygous long-hair with heterozygous long-hair [LL] x  [Lk]Â

Possible combinations: [LL Lk LL Lk]Â

Results  in: 100% visibly long-hair Havanese, of which half (50%) are Homozygous, the  other half (50%) are Heterozygous.Â

4.Heterozygous long-hair with Heterozygous long-hair [Lk] x  [Lk]

Possible combinations: [LL Lk Lk kk]

Results  in: 25% Homozygous long-hair Havanese, 50% Heterozygous long-hair Havanese and  25% Homozygous short-haired Havanese.Â

5.Homozygous long-hair with Homozygous short-hair [LL] x [kk]

Possible combinations: [Lk Lk Lk Lk]

Results in: 100% Heterozygous long-haired  Havanese

6.Heterozygous long-hair with Homozygous short-hair [Lk] x [kk]

Possible combinations: [Lk Lk kk kk]

Results  in: 50% Heterozygous long-haired and 50% (homozygous short-haired Havanese)

The  percentages expected for the resulting descendants are not valid for a  particular litter, but for the overall breeding of that type. Recessive genes can be carried along over many generations completely unnoticed because they can only be seen (phenotype) when they occur in double dose, by the mating of two  heterozygous, or "carrier" animals. One can never be certain whether a particular Havanese is pure long-haired. ( Even an incest mating would not be certain proof.)

One fact is certain however, and that is when a smooth-coat  Havanese is produced form two long-haired parents, BOTH the mother and father are heterozygous carriers of the recessive gene.

At the present time there are no breeding restrictions that can be employed without taking whole lines out of the breed and thus endangering the genetic health of the breed. For the time being, the only measure that should be enforced is that these smooth coated dogs which do not conform to the standard must not be used for breeding. It is up to the individual breeder to examine the lineage of his breeding pairs for consanguinity of ancestors which might be  carriers and to breed responsiblyduals.