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Home » Archive » 2013

TDK conference 2013

Genetic Backgrounds of Hair Length in German Shepherd Dogs
Tóth Klaudia - year 4
SzIU, Faculty of Veterinary Science, Departmen for Animal Breeding, Nutrition and Laboratory Animal Science
Supervisor: László Zöldág DVM

Abstract:

The author has studied the inheritance of hair type (hair length, short-and long) in Hungarian kennel club of elite show and working German shepherd dogs.

Data were collected from 76 show and 25 working dog's litters, and the pedigrees were analyzed for three to ten year long period. She has estimated the genotype (heterozygote or homozygote) based on phenotype and segregation data from two generations (parents and puppies). On the base of the family tree examinations she has come to the following conclusions.

The inheritance of the hair length follows the Mendelian rules, but the epistasis, the varying gene expression and epigenetic (transcription) factors may influence the phenotype appearance. Examinations have confirmed the validity of Mendelian rules; accordingly the short hair is dominant (it seems sometimes not completely dominant, only semidominant) and supposedly with dosage effects (homozygote is always shorthaired), and the long hair (with varying expression) descends to be recessive. Changes in expression of the long hair may be seen mainly in heterozygote individuals, they may show short hair (complete dominance) and also half long and long hair in their phenotype.

Supposedly, the fibroblast growth factor (FGF5) and it's mutations (C59F) are responsible for the long hair in German Shepherd dog and some other breeds as well. It has been shown and demonstrated also by the author’s phenotype and segregation analysis in crossings of heterozygous parents. In these studies it cannot be excluded that the dominant long hair allele assumed by Burns and Frases in dogs (1966), may also be present in the genetic structure of German shepherd dogs. Most of the breeders are thinking about the long hair phenotype as a recessive characteristic. Accordingly, the short hair is dominant, the long hair is recessive, what our experiments and also the segregation data of litters have verified, with the supplement, that other factors may also interact with the dominant and recessive alleles. For example, the epistasis (epistatic and complementary polygenic effects) and epigenetic (environmental and transcription factors, nutrition) may also play a partial role in the inheritance and manifestation of the hair length. These expression differences were seen frequently in heterozygous genotypes (Ll) where the short hair is not always completely dominant (only semidominant or intermediate) and the coat quality may show a semi long or seemingly long character.

Based on the Hardy-Weinberg rule the allelic and genotype frequencies were also calculated in the Hungarian German Shepherd dog population.



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