directive information entity target subfragment specification PERSON:Philippe Rocca-Serra PRS for OBI http://www.ncbi.nlm.nih.gov/pubmed/23335919 "performing a profiling of microbial phylogenetic composition using massively-parallel pyrotag sequencing targeting the V9 hypervariable region (used as target subfragment) of the 18S ribosomal RNA (rRNA) gene (used as target gene) is a directive information specifying a genomic region, possibly located in a coding genomic region, which is the focus of a planned process such as an assay, for instance in a environmental gene survey target subfragment target subfragment specification ready for release