HYBRIDdb: a database of hybrid genes in the human genome

HYBRIDdb is a database of hybrid genes in humans. This system encompasses the bioinformatics analysis of mRNA, EST, cDNA, and genomic DNA sequences in the INDC databases, and can be used to identify hybrid genes. We searched for hybrid genes among the 28,171 genes listed in the NCBI database, and analyzed their structural patterns in the human genome. The 2,344 gene pairs were detected as hybrid forms of transcriptional products. We classified the hybrid genes into two groups: chromosomal-mediated translocation fusion transcripts and transcription-mediated fusion transcripts.The HYBRIDdb database will provide genome scientists with insight into potential roles for hybrid genes in human evolution and disease.Hybrid genes are created by trans-splicing, sense/antisense transcription, genome rearrangement, or intergenic splicing between two genes [1-5]. The creation of new genes is a potential risk factor for tumor development, yet may also promote diversification by inducing gene substitution, translocation, inversion, or rearrangement [1,6-8]. As a result, hybrid genes have the ability to be either harmful or advantageous to humans [9,10].Cancer genes have somatic mutations similar to chromosomal translocations that result in hybrid transcripts by apposing one gene to the regulatory regions of another. For example, a hybrid transcript is created by genomic rearrangement of the mixed-lineage leukemia (MLL) gene at 11q23 and the septin family (SEPT6) gene at Xq24 in acute leukemia patients [11]. These rearrangements result in fusions with at least 40 other genes, resulting in expression of hybrid proteins with leukemogenic activity [12,13]. Occasionally hybrid gene formations can also contribute to genomic diversity. Normal forms of UEV proteins are located in the nuclei of cells, while Kua proteins are distributed in endomembranes. The abnormal fusion transcript of these proteins, however, has new enzymatic activity that is associated with cytoplasmic structures [9,14,