Repeat polymorphism analysis for examining genetic variability and the implications for specific traits in dog breeds.

Genetic variations of functional genes in various animal species have been previously examined to understand the relationship between genotypes and phenotypes. Repeat polymorphism can be found in not only coding sequences but also untranslated regions of the protein-coding genes, affecting gene regulation via a variety of mechanisms. In this respect, repeat polymorphisms including microsatellites, variable number of tandem repeats (VNTRs), and short interspersed nuclear elements (SINEs) in relation to functional genes contribute to recognition of genetic or phenotypic variation and individual identification. These elements are biologically valuable markers for studies on association between genetic make-up and behavioral patterns in dog breeds. Hence, to examine the effect of genotype on behavior, studies on this combination are certainly important. Hence, this review could cast light on the functional roles of repeat polymorphisms in dog behavior and breed variation.