Abstract
To assess factors for canine skin extensibility, our study investigated associations between the dogs' skin extension index and the following factors, gender, age, neuter status, weight, coat color and six coat color related gene polymorphisms. Swab samples were collected from 69 toy poodles to extract DNA. The skin extension indices of the lower back and the neck were measured using the following formula: vertical height of the skin fold divided by body length multiplied by 100. The dogs' age, weight, gender, neuter status and coat color were also recorded, as well as polymorphisms of the following six selected coat color related genes, Melanocortin 1 receptor, Tyrosinase-related protein 1, Melanophilin, Canine β-defensin-1, Major Facilitator Superfamily Domain Containing 12 and Agouti-signaling protein (ASIP). Univariable analysis showed there was a meaningful association between the lower back skin extension index and both gender and age (P<0.001 and P=0.048, respectively). Also, there was a possible association between the lower back skin extension index and ASIP Single nucleotide polymorphism (SNP) (R96C) (P=0.078). Linear model analysis showed there was a significant association between the lower back skin extension index and gender (P<0.001), and there was a tendency of the association between the lower back skin extension index and ASIP SNP (R96C) (P=0.098). In addition, there was an association between gender and age for the skin extension index. (P=0.048). Therefore, these results suggest that a greater risk of skin extensibility in toy poodle could be related to being female and the ASIP SNP (R96C), because these factors were associated with higher lower back skin extension index.