Identification of Cryptic Allele for Merle Patterning in Dogs by Molecular Genetics Methods / Identifikacija Skrivenog Alela Za Mramoriranu Šaru Pasa Pomoću Metoda Molekularne Genetike

Merle patterning in dogs, caused by the insertion of a short interspersed element (SINE) in the genetic structure of SILV gene, is characterized by patches of diluted pigment intermingled with normal melanin. Sequencing analyses of SINE element localized in the canine SILV gene discovered a variability of the poly (A)-tail length which is responsible for the different expression of merle pattern. The SINE element with the length of poly(A)-tail between 91 - 101 nucleotides is responsible for the merle phenotype with all characters of merle pattern. On the contrary the dogs which have SINE element with the shorter length of poly(A) tail between 54-65 nucleotides are referred as cryptic merles without expresion of Merle pattern. The aim of this study was to improve molecular genetics method for the detection of cryptic allele for merle patterning in dogs. A total of 40 dogs of four breeds - Border collie, Shetland sheepdog, Australian Shepherd dog, and Chihuahua were used in this study. Canine genomic DNA was isolated from samples of whole blood and buccal cells by commercial column kit. Detection of merle (M), cryptic merle (Mc) and non-merle (m) alleles was done using M13-tailed primer protocol and two different allele-sizing methods for the verification of the electrophoresis result. In the analyzed population of dogs were detected 20 dogs with non-merle genotype mm, 17 dogs with merle genotype Mm, 2 dogs with double merle genotype MM and one dog with merle phenotype but with the presence of cryptic merle allele Mc with the consequential genotype MMc.