General RNAi FAQs

• What is RNAi?  Why do I want to do RNAi?
• What is a gene accession number?
• What are RefSeq Numbers?
• Where do I find RefSeq Numbers?
• I cannot find my target gene in your YFG search engine.  Do you have it?
• Why can’t I find my gene using my gene symbol?
• For what species do you have predesigned siRNA or shRNA products?
• What does it mean if I cannot find my target gene?

What is RNAi?  Why do I want to do RNAi?
RNAi means RNA interference.  This technology allows researches to knockdown certain genes to further understand functionality.

What is a gene accession number?
The accession number is the unique identifier assigned to the entire sequence record when the record is submitted to GenBank. The GenBank accession number is a combination of letters and numbers that are usually in the format of one letter followed by five digits (e.g., M12345) or two letters followed by six digits (e.g., AC123456).

What are RefSeq Numbers?
The Reference Sequence (RefSeq) collection aims to provide a comprehensive, integrated, non-redundant set of sequences, including genomic DNA, transcript (RNA), and protein products, for major research organisms.

RefSeq standards serve as the basis for medical, functional, and diversity studies; they provide a stable reference for gene identification and characterization, mutation analysis, expression studies, polymorphism discovery, and comparative analyses. RefSeqs are used as a reagent for the functional annotation of some genome sequencing projects, including those of human and mouse. (From NCBI)

Where do I find RefSeq Numbers?
NCBI
Entrez Nucleotides database, in NCBI, is a collection of sequences from several sources, including GenBank, RefSeq, and PDB.

Human Gene Nomenclature (HGNC)
HGNC operates under the Human Genome Organization (HUGO) and provides unique and meaningful names and symbols to over 22,000 genes.

Mouse Genome Informatics (MGI)
MGI provides integrated access to data on the genetics, genomics, and biology of the laboratory mouse.

I cannot find my target gene in your YFG search engine.  Do you have it?
YFG focuses on mouse and human specific genes, there are a few rat genes included, but we typically only show mouse and human.  Please verify the gene you are looking for is human or mouse and provide us with any information you might have concerning your gene of interest.  If applicable we will log the change.

Why can’t I find my gene using my gene symbol?
The symbol associated with your gene may have changed. We recommend you visit NCBI, HGNC, or MGI for symbol verification.

For what species do you have predesigned siRNA or shRNA products?
For siRNA, we offer human, rat, and mouse.  For shRNA, we offer human and mouse.

What does it mean if I cannot find my target gene?
The collection is currently being cloned. New target genes will be introduced on a quarterly basis until the library is completed. It is possible your target gene is not in the current collection, but may be coming in future releases. Also, it is possible that alternate accession numbers or gene symbols may be used for your gene of interest. Please check NCBI, for up-to-date information. Please contact us at MISSIONRNAi@sial.com for more information on constructs currently in production.

For additional questions regarding our siRNA and shRNA product lines, please select one of the links below:

shRNA FAQs