NCBI FieldGuideA Field Guide Genome resources Sequence similarityNCBI FieldGuideGenome ResourcesLocusLinkLocusLinkGene databaseGene databaseUniGeneUniGeneTrace ArchiveTrace ArchiveMap ViewerMap ViewerHomologeneHomologeneNCBI FieldGuideGenomic BiologyNCBI FieldGuideNCBI FieldGuideNCBI FieldGuideNCBI FieldGuideGenome Projects: microbNCBI FieldGuideNCBI FieldGuideNCBI FieldGuideGenome ResourcesLocusLinkLocusLinkGene databaseGene databaseUniGeneUniGeneTrace ArchiveTrace ArchiveMap ViewerMap ViewerHomologeneHomologeneNCBI FieldGuideA single query interface to Sequences - RefSeqs - GenBank - Homologene Maps MapViewer Entrez linksLocusLinkLocusLink will be replaced by Entrez Gene on MARCH 1, 2005. Check Gene FAQ for current information.NCBI FieldGuideEntrez GeneLocusLinkA single query interface to Sequences- RefSeqs- GenBank- Homologene Maps MapViewer Entrez linksEntrez Gene More organisms - all RefSeq genomes Entrez integrationNCBI FieldGuideGsnsym淀粉样变性病NCBI FieldGuideNCBI FieldGuideGlobal Entrez: NADH2nadh247NCBI FieldGuideEntrez Gene: NADH226 recordsNCBI FieldGuideGene Record for Pongo NADH2Homo sapiensNCBI FieldGuideDisplay Exons/Introns: Gene TableNCBI FieldGuideGene TableNCBI FieldGuideA Record With More Data: Human HFE血色沉着病NCBI FieldGuideGene Graphic LinksNM_NP_NCBI FieldGuideIntrons/Exons: Gene Tablelinks to sequenceNCBI FieldGuideA Record With More Data: Human HFENCBI FieldGuideEntrez SNPhfegene name AND humanorgn 52血色沉着病NCBI FieldGuideLinking to SNP染色体定位基因定位序列定位NCBI FieldGuideSNP in StructureNCBI FieldGuideLink to OMIMNCBI FieldGuideVariants in OMIMNCBI FieldGuideGenome ResourcesLocusLinkLocusLinkGene databaseGene databaseTrace ArchiveTrace ArchiveMap ViewerMap ViewerHomologeneHomologeneUniGeneUniGeneNCBI FieldGuideGene-oriented clusters of expressed sequences Automatic clustering using MegaBlast Each cluster represents a unique gene Informed by genome hits Information on tissue types and map locations Useful for gene discovery and selection of mapping reagentsUniGeneNCBI FieldGuideA Cluster of ESTsquery5 EST hits3 EST hitsNCBI FieldGuideUnigeneNCBI FieldGuideUniGene CollectionsNCBI FieldGuideExample UniGene ClusterNCBI FieldGuideHistogram of cluster sizes for UniGene Hs build 177NCBI FieldGuideUniGene Cluster Hs.95351NCBI FieldGuideUniGene Cluster Hs.95351NCBI FieldGuideUniGene Cluster Hs.95351: expressionNCBI FieldGuideUniGene Cluster Hs.95351: seqsNCBI FieldGuideDownload sequencesweb pageftp siteNCBI FieldGuideGenome ResourcesLocusLinkLocusLinkGene databaseGene databaseUniGeneUniGeneTrace ArchiveTrace ArchiveMap ViewerMap ViewerHomologeneHomologeneNCBI FieldGuideThe New HomologeneAutomated detection of homologs among the annotated genes of completely sequenced eukaryotic genomes. No longer UniGene based Protein similarities first Guided by taxonomic tree Includes orthologs and paralogsNCBI FieldGuideOrthologs 和 Paralogs 是同源序列的两种类型。Orthologs（垂直同源基因）是指来自于不同物种的由垂直家系（物种形成）进化而来的蛋白，并且典型的保留与原始蛋白有相同的功能。Paralogs（平行同源基因）是那些在一定物种中的来源于基因复制的蛋白，可能会进化出新的与原来有关的功能。请参考文献获得更多的信息。NCBI FieldGuidegene duplicationParalogs vs Orthologsearly globin geneA-chain gene B-chain genefrog A chick A mouse Amouse B chick B frog Bparalogsorthologs orthologsNCBI FieldGuideThe New HomologeneHomologene Build 37.2Species Number of genesinput grouped groupsNCBI FieldGuideRAG1 Homologenerag112recombination activating gene NCBI FieldGuideRAG1 HomolgeneRAG1 Amniota NCBI FieldGuideHomolgene: RAG1NCBI FieldGuideNCBI FieldGuideHomolgene: RAG1NCBI FieldGuideGenome ResourcesLocusLinkLocusLinkGene databaseGene databaseUniGeneUniGeneTrace ArchiveTrace ArchiveMap ViewerMap ViewerHomologeneHomologeneNCBI FieldGuideNCBI FieldGuideNCBI FieldGuideNCBI FieldGuideMapViewerNCBI FieldGuideList ViewNCBI FieldGuideHuman MapVieweradar腺甙脱氨酶NCBI FieldGuideMapViewer: Human ADAR4NCBI FieldGuideMV Hs ADAR3 UTR5 UTRNCBI FieldGuideMaps uses as query very sensitive protein search RPS BLAST searches a database of PSSMs tool for conserved domain searchesNCBI FieldGuide Widely used similarity search tool Heuristic approach based on Smith Waterman algorithm Finds best local alignments Provides statistical significance All combinations (DNA/Protein) query and database. DNA vs DNA blastn DNA translation vs Protein blastx Protein vs Protein blastp Protein vs DNA translation tblastn DNA translation vs DNA translation tblastx www, standalone, and network clientsBasic Local Alignment Search ToolNCBI FieldGuideTranslated BLASTQueryDatabaseProgramNPucleotideroteinNNNNPPblastxtblastntblastxPPPPPPPPPPPPPPPPPPPPPPPPParticularly useful for nucleotide sequences without protein annotations, such as ESTs or genomic DNANCBI FieldGuideHow BLAST Works Make lookup table of “words” for query Scan database for hits Ungapped extensions of hits (initial HSPs) Gapped extensions (no traceback) Gapped extensions (tr