imprinting analysis of porcine dio3 gene in two fetal stages and association analysis with carcass and meat quality traits imprinted genes play important roles in mammalian growth development and behavior in this study we obtained 1568 bp mrna sequence of porcine dio3 deiodinase iodothyronine type iii and also identified its imprinting status during porcine fetal development the complete open reading frame orf encoding 278 amino acids the porcine dio3 mrna was expressed predominantly in backfat mildly in liver uterus kidney heart small intestine muscle and stomach and almost absent in spleen and lung a single nucleotide polymorphism in exon ac 687 was used to investigate the allele frequencies in different pig breeds and the imprinting status in porcine embryonic tissues the results indicate that dio3 was imprinted in all the tested tissues statistical analysis showed the dio3 gene polymorphism was significantly associated with almost all the fat deposition and carcass traits including lean meat percentage lmp fat meat percentage fmp ratio of lean to fat rlf shoulder fat thickness sft sixthseventh rib fat thickness rft buttock fat thickness bft loin eye area lea and intramuscular fat imf