Merle allele variations in the Mudi dog breed and their effects on phenotypes

Area of Science:

• Canine genetics
• Coat color genetics
• Molecular biology

Background:

• The merle phenotype in dogs is caused by retrotransposon insertions in the SILV gene, affecting pigment cell function.
• Previous research linked short interspersed element (SINE) insertion size to merle attributes but couldn't definitively classify coat patterns.
• Variations in merle alleles can lead to complex coat colorations and potential health concerns.

Purpose of the Study:

• To analyze merle allele variations and their frequencies within the Mudi dog breed.
• To determine the precise lengths of merle alleles using advanced genotyping techniques.
• To highlight the genetic basis of merle coat patterns and its implications for breeding.

Main Methods:

• Genotyping of 123 Mudi dog samples from 11 countries.
• Automated fluorescent capillary fragment analysis to determine merle allele lengths.
• Analysis of short interspersed element (SINE) insertion sizes in the SILV gene.

Main Results:

• The classic merle genotype (m/M) was most common (61.8%) in the Mudi samples.
• Atypical (5.7%), harlequin (13.8%), and mosaic (17.9%) merle genotypes were also identified.
• A low frequency of the double merle genotype (M/M) was observed (0.8%).

Conclusions:

• Genetic testing for merle alleles is essential, as 'hidden merle' dogs can produce offspring with health issues.
• Understanding merle genotype distribution in breeds like the Mudi aids in responsible breeding practices.
• Accurate genotyping prevents unintentional breeding of double merle dogs, mitigating associated ophthalmologic, viability, and auditory impairments.