Entrez Quiz

Q. Find the NCBI contig (eg NT_ 011520) of which AC005006 is a component.

A. Search Entrez “nucleotides” with AC005006. Select “Assembly” in the Display pulldown and press the “Display” button.

Q. Generate a list of the components comprising NCBI contig NT_011520.

A. Start where you left off in the example above and choose “Components” in the Display pulldown. Then press “Display” to show the components of the contig.

Q. Retrieve the UniGene cluster IDs for a list of 50 human mRNA RefSeqs (eg. NM_130786).

A. Put a list of the accessions, one per line, into a text file. Upload this file using Batch Entrez at:

When the document summary giving links to each accession is returned, use the Display pulldown to select “UniGene Links”. Then press the Display button to display the list of UniGene clusters corresponding to the list of RefSeqs.

Q. Beginning with a list of human mRNA RefSeq accessions, generate a list of corresponding protein RefSeq accessions.

A. Upload the mRNA accession list, as above. From the resulting document summary, choose “Protein Links” from the Display pulldown and press Display.

Q. Find all viral 3D structure records which include two DNA chains.

A. Search Entrez Structures with “viruses[orgn] AND “2”[DNAChain Count]”. Click on the “Preview/Index” link to see more fields.

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