In general, the results from the two databases are consistent. Some results of mammals obtained from TGI are lower than UniGene's. It's probably because some of TGI's data are too old, or because there are real differences in the average number of alternative splicing among mammals, but if so, it will be difficult to understand the huge difference between mouse and rat. At the present time, although the transcriptome data (clustered EST data) of many species are available, most of them are incomplete.