Gene identification on chromosome 18

Several regions on human chromosome 18 have demonstrated linkage to bipolar disorder. To identify the genes on 18, exon trapping was performed on the whole chromosome using 3,000 chr 18 specific cosmid clones. Over 883 unique exon sequences have been isolated. Sequence analysis revealed that 122 sequences are from 41 of the 80 known genes on chr 18, 161 are identical to ESTs, 49 have significant homology to genes from human and other species. Search of the GenBank high throughput genome sequence database indicated that approx. 70% of the trapped exons showed identity to chr 18 genomic sequences. To further study the gene content of chr 18, computer algorithms were used to predict genes within finished sequences. MZEF was used to predict exons (30-40 exons per 200 kb sequence), while GenScan was used to predict ORF's. We have analyzed 22 sequence contigs on chr 18 and predicted 100 ORF's in these sequences. Further analyses of trapped exon sequences and comparison with the computer predictions (of exons and ORF's) will greatly assist in the characterization of genes.