Sequence Analysis of a Total of Three Megabases of DNA in Two

Large-scale sequencing of genomic regions and in silico gene trapping together represent a highly efficient and powerful approach for identifying novel genes. We performed megabase-level sequence analyses of two genomic regions on human chromosome 8p (8pll.2 and 8p22—»p21.3), after covering those segments with sequence-ready contigs composed of 74 cosmids, 14 BACs, and three PAC clones. We determined continuous nucleotide sequences of 1,856,753 bases on 8pll.2 and 1,210,381 bases on 8p22—>p21.3 by combining the shotgun and primer-walking methods. In silico gene trapping identified four novel genes in the 8pll.2 region and, in the 8p22-»p21.3 region, six known genes (PRLTS, PCM1, MTMR7, HCAT2, HFREP-1 and PHP) and three novel genes. The distribution of Alu and LINE1 repetitive elements and the densities of predicted exons were different in each region, and Alu-nch portions contained more exonic sequences than LINEl-rich areas. Key words: large-scale DNA sequencing; physical and transcriptional maps; human chromosome 8pll.2; human chromosome 8p22—>p21.3 1