Dazzling Graphics
with Cn3D 3.0
HomoloGene:
Clusters of Clusters
Fly Genome Deposited
in GenBank
Drosophila Finds
New Home Page
Frequently Asked
Questions
Frequently Asked Questions
In PubMed, how can I restrict my search to an author name?
Click on the Preview/Index link in the grey area beneath the query box. Choose Author Name from the Index list box and type the author name into the text box to the right. Click on the AND button to add the author name to your query.
Why do I get the message “ERROR: Blast: No valid letters to be indexed?”
You may have accidentally entered an accession number in the search box without changing the input selection from Sequence in FASTA format to Accession or gi. You will also see this error message if your query contains invalid characters or a large number of ambiguity codes (R,Y,K,W,N, etc. for nucleotide). Although BLAST allows ambiguity codes, be aware that these will always contribute a negative value to nucleic acid alignment scores.
How are symbols and gene names selected for LocusLink and RefSeq records?
Both LocusLink and RefSeq use gene symbols and gene names established by the nomenclature committee appropriate for the genome.
How can I see the sequence alignments in GenBank?
From the Entrez Nucleotides search screen, click on the Limits button, and then select Properties from the search field list box. Type in “seqalign present” in the search box and press Go. To view an alignment, follow the Popset link to the right of the Entrez summary.
Is there a way to download the proteome of an organism from GenBank?
Yes, if the organism is represented in Entrez Genomes. Navigate to the Entrez Genomes summary page for the organism in question and click on the Protein Coding Genes link in the Feature table. A table will be displayed giving the protein coding regions of the genome and links to corresponding protein sequences. This table, as well as the corresponding protein sequences, can be saved to a local file. Entrez Genomes is found at www.ncbi.nlm.nih.gov/Entrez/Genome/main_genomes.html.
Where can I find tutorials on the use of the NCBI Web services?
A set of NCBI tutorials as well as other educational material can be found under the Education link on the NCBI home page.
