We sequenced exon IV of COMT gene in search for novel polymorphisms and then genotyped four out of five identified by direct sequencing , using TaqMan assay on 266 opioid-dependent and 173 control subjects .
O O O O O B-GeneOrGeneProduct O O O O O O O O O O O O O O O O O O O O O O O B-ChemicalEntity O O O O O