A rejtett cifra szín molekuláris genetikai módszerekkel való kimutatása mudi fajtában

Abstract

SUMMARY Background: The merle colour in dogs (merle: blackbird) is caused by a retrotransposon insertion in the SILV gene, resulting in malfunction in the eumelanin producing pigment cells. In homozygous (MM) individuals congenital auditory and ophthalmologic disorders are common, therefore the mating of two heterozygous (Mm) dogs should be avoided, and is in fact forbidden in case of breeds having this trait. Some of the colours, however are fully characterised by pheomelanin pigment (e. g. cream, beige, fawn), which are not affected by the merle gene, making it impossible to recognize the heterozygous individuals based on their phenotype (hidden merles).Objectives: The author’s aim was to test a fast, reliable and cost-efficient genetic method in the Mudi breed, because in this breed along with the merle colour, white and fawn colours can also be found– which increases the chance for hidden merle individuals.Materials and Methods: In their study the authors used 23 hair or buccal swab samples collected from Hungarian and foreign possible hidden merle Mudi dogs, then multiplied the exon 11 of the SILV gene with polymerase chain reaction (PCR) method from the purified DNA. Agarose gel electrophoresis was used to detect the PCR products (M and m alleles) and to separate them by size. The authors compared their genotype results with the dogs' phenotypic traits (colour of the eyes and the fur).Results and Discussion: According to practical observations blue or partial blue eyes are solely caused by the merle gene in the Mudi breed, this observa-tion was confirmed by the authors' DNA test, so in these simple cases hidden merle dogs can be detected by their phenotype. However, eye colour is not always affected by the merle gene: in this research 4 of the 17 brown eyed dogs tested proved to be heterozygous Mm. This indicates that the genetic test is the only reliable way to identify hidden merle individuals, which is important to prevent puppies with decreased viability.