TY - JOUR T1 - <em>NR6A1</em> Allelic Frequencies as an Index for both Miniaturizing and Increasing Pig Body Size JF - In Vivo JO - In Vivo SP - 163 LP - 167 DO - 10.21873/invivo.12244 VL - 35 IS - 1 AU - MOE IJIRI AU - YU-CHANG LAI AU - HIROAKI KAWAGUCHI AU - YOSHIKAZU FUJIMOTO AU - NAOKI MIURA AU - TOMOHIDE MATSUO AU - AKIHIDE TANIMOTO Y1 - 2021/01/01 UR - http://iv.iiarjournals.org/content/35/1/163.abstract N2 - Background/Aim: The number of vertebrae in swine varies from 19 to 23 and is associated with body size. Nuclear receptor subfamily 6 group A member 1 (NR6A1) is considered a strong candidate for affecting the number of vertebrae in swine. Wild boars, which uniformly have 19 vertebrae, have the wild type allele while multi-vertebrae European commercial pigs have the mutated allele. Our aim was to confirm the factor of the miniaturization. Materials and Methods: We examined vertebrae number and NR6A1 polymorphism in the Microminipig and three domestic breeds that vary in body size. Results: The Microminipig had 19 or less vertebrae and a wild type NR6A1 genotype. Three domestic breeds had more than 21 vertebrae while the largest vertebrae number was observed in multi-vertebrae-fixed Large White. Heterozygous genotypes were observed in the middle-sized indigenous pig while homozygous NR6A1 mutations were observed in European commercial breeds. Conclusion: NR6A1 could be a useful index for both miniaturizing and increasing pig body size. ER -