Genes & Genomes

• What are accession numbers at NCBI?

• What are NCBI Reference Sequence (RefSeq) accession numbers and what information is embedded in their format?

• How do I use Gene records at NCBI to find and download all SNPs that are associated with a human gene?

• On what sequences do you base NCBI Taxonomy classification and the Taxonomy Common Tree?

• Why do I see square brackets around some organism names in the NCBI Taxonomy database?

• How are organisms in the NCBI Taxonomy database formally named?

• What does 'genomic clone has been placed' really mean?

• How do I obtain the current human proteome sequences from NCBI?

• How do I access information on genomic clones at NCBI?

• How do I obtain a transcript and protein sequence for a gene by using the NCBI Gene database?

• What are the sources of the NCBI Protein database sequences?

• What was the reason for the removal of a prokaryotic RefSeq protein record and how do I find its replacement at NCBI?

• How do I search NCBI Protein database for sequences that belong to a protein family?

• Why are genomes sequenced?

• How are genome assemblies generated and what are assembly levels?

• What is nucleotide sequence/genome annotation?

• What are genomic-clone libraries and how are they made?

• What are the data sources for the expression displays on the Genome Data Viewer at NCBI?

• How do I obtain a genomic sequence record for a gene using the NCBI Gene database?

• What is the number of the NCBI Protein database records and does each record represent a unique sequence?

• How can I find tissue-specific expression data for a gene of interest at NCBI?

• What types of genomic sequences are archived in the NCBI Nucleotide database for an organism?

• How do I use Gene records at NCBI to access human variation data in Variation Viewer?

• How do I obtain subsets of the human proteome at NCBI?

• How do I locate a RefSeq or UniProtKB (Swiss-Prot) sequence that is identical to my protein of interest at NCBI?

• Is there a whole genome sequence for my organism of interest at NCBI?

• How do I find the complete taxonomic lineage for an organism at NCBI?

• How do I access all sequence records for a genome assembly on the NCBI web?

• When I search your database for a gene, I obtain too many records. What sequence record should I choose?

• How do I find variation information and associated phenotypes for a human gene at NCBI?

• How do I find specific gene expression studies at NCBI?

• How can I compare expression of a gene of interest between different tissues at NCBI?

• How do I obtain a curated set of proteins for my organism or taxonomic group at NCBI?

• How are GenBank protein sequences determined?

• What are genome assembly accession numbers at NCBI?

• Where and how do I retrieve human mitochondrial genome sequences, including those from human genealogy studies?

• How do I find GenBank records annotated with variation features?

• What is a genome assembly?

• Who generates genome assemblies that are present in the NCBI databases?

• What are reference genomes and how can you find these at NCBI?

• Why are the Entrez Genome and Assembly web pages gone?