Allelic Frequencies as an Index for both Miniaturizing and Increasing Pig Body Size.

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.