NCBI will discontinue both the NCBI Genomes (chromosome) and the Human ALU repeat elements (alu_repeats) BLAST databases in October 2017.
Better alternatives to NCBI Genomes (chromosome)
The existing NCBI Genomes (chromosome) database does not offer complete and non-redundant coverage of genome data. The newly added NCBI RefSeq Genomes Database (refseq_genomes) and the RefSeq Representative Genomes Database (refseq_representative_genomes) are more useful alternatives to the chromosome database. You can select these databases from the database pull-down list on any general BLAST form that searches a nucleotide database (blastn, tblastn).
Figure 1. The nucleotide-nucleotide BLAST database menu with the recommended (RefSeq Genome and Representative genomes) and deprecated (NCBI genomes (chromosomes) and Human ALU repeats) databases highlighted.
This article is intended for GenBank data submitters with a basic knowledge of BLAST who submit sequence data from protein-coding genes.
One of the most common problems when submitting DNA or RNA sequence data from protein-coding genes to GenBank is failing to add information about the coding region (often abbreviated as CDS) or incorrectly defining the CDS. Incomplete or incorrect CDS information will prevent you from having accession numbers assigned to your submission data set, but there is a procedure that will help you troubleshoot any problems with the CDS feature annotation: doing a BLAST analysis with your sequences before you submit your data.
Here’s how to use nucleotide BLAST (blastn) and the formatting options menu to analyze, interpret and troubleshoot your submissions:
1. To start the BLAST analysis, go to the BLAST homepage and select “nucleotide blast”.
Figure 1. Select “nucleotide blast”.