TIGR Gene Idices，TIGR基因索引是TIGR维护的物种特异的基因和EST（表达序列标签）数据库，其中TIGR是The Institute for Genomic Research的缩写。目前该数据库已包含动物、植物、原生生物、真菌四大类87个物种的基因索引，每年数据升级三次。网站界面很友好，点击首页的某个物种图标就可以进入相应物种的基因索引。IGR Gene Idices收录的基因数据不是简单的对GenBank的基因和EST数据按物种分类，而是从GenBank中提取不同物种的EST和注释的基因序列，通过聚类、拼接等分析过程(TIGR Assembler (Sutton et al. 1995,Genome Science and Technology 1: 9-19))，产生唯一的(unique)、高可信度的虚拟转录本或者是假设性一致序列(Tentative Consensus sequences)，这种假设性一致序列便可用来提供假定基因数据，可以成为联系转录本与基因作图、基因组数据，联系直系同源和旁系同源基因的桥梁。

English Summary

Database DescriptionExpressed Sequence Tags (ESTs) have provided a first glimpse of the collection of transcribed sequences in a variety of organisms. However, a careful analysis of this sequence data can provide significant additional functional, structural, and evolutionary information. Our analysis of the public EST sequences, available through the TIGR Gene Indices (TGI; http://www.tigr.org/tdb/tdb.html), is an attempt to identify the genes represented by that data and to provide additional information regarding those genes. Gene Indices are constructed for selected organisms by first clustering, then assembling EST and annotated gene sequences from GenBank. This process produces a set of unique, high-fidelity virtual transcripts, or Tentative Consensus (TC) sequences. The TC sequences can be used to provide putative genes with functional annotation, to link the transcripts to mapping and genomic sequence data, and to provide links between orthologous and paralogous genes.