It is important to be able to retrieve, quickly and easily, any number
of sequences matching any given specific criteria from the huge amount of data
that can be found in the databases.
The Entrez retrieval system at NCBI is useful because many of its records
are linked to other records, either in the same database, or between databases.
Links can be similar sequences, either within or between databases
(e.g. similar nucleotide sequences, or similar nucleotide and protein sequences).
Narrowing down a search, term-by-term, is also a useful feature.
Batch Entrez allows you to retrieve large sets of sequences
from a list of accession numbers.
In the SRS retrieval system, there are many searchable databases, which can be
cross-referenced using WWW links, which allows the user to find out a
lot of information about a particular sequence very quickly and easily. Both the SRS
retrieval system and the NCBI Entrez system allow you to get both protein and
nucleotide sequences.
Entrez Gene is a database that contains functional information
and map locations about genes. It is available from the main page as a separate database,
and should not be confused with the nucleotide database.
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