NCBI : GenBANK
http://www.ncbi.nlm.nih.gov
 GenBank:
An annotated collection of all publicly available nucleotide and amino acid sequences.
 EST database:
A collection of expressed sequence tags, or short, single-pass sequence reads from mRNA (cDNA).
 GSS database:
A database of genome survey sequences, or short, single pass genomic sequences.
 HTG database:
A collection of high throughput genome sequences from large-scale genome sequencing centers; including unfinished and finished sequences.
 SNPs database:
A central repository for both single base nucleotide substitutions and short deletion and insertion polymorphisms.
 RefSeq:
A database of non-redundant reference sequences standards, including genomic DNA contigs, mRNAs and proteins for known genes. Multiple collaborations, both within NCBI and with external groups, support our data-gathering efforts.
 STS database:
A database of sequence tagged sites; or short sequences that are operationally unique in the genome.
 UniSTS:
A unified, non-redundant view of sequence tagged sites (STSs).
 UniGene:
A collection of ESTs and full-length mRNA sequences organized into clusters, each representing a unique known or putative human gene annotated with mapping and expression information and cross-references to other sources.
NCBI