High-resolution transcript map of the region spanning D12S1629 and D12S312 at chromosome 12q13: triple A syndrome-linked region.

For those searching for human disease-causing genes, information on the position of genes with respect to genetic markers is essential. The physical map composed of ESTs and genetic markers provides the positional information of these markers as well as the starting point of gene identification in the form of genomic clones containing exons. To facilitate the effort of identification of genes in the region spanning D12S1629 and D12S312, we constructed a high-resolution transcript map with PAC/BAC/cosmid clones. The strategy for the construction of such a map involved utilization of STSs for the screening of the large insert bacterial chromosome libraries and a chromosome 12-specific cosmid library by hybridization. The contig was constructed based on the STS contents of the clones. The resulting high-resolution transcript map of the region between P273P14/SP6 and D12S312 spans 4.4 cM from 66.8 to 71.2 cM of the Généthon genetic map and represents approximately 2.4 Mb. It was composed of 81 BAC, 45 PAC, and 91 cosmid clones with a minimal tiling path consisting of 16 BAC and 4 PAC clones. These clones are being used to sequence this part of chromosome 12. We determined the order of 135 STSs including 74 genes and ESTs in the map. Among these, 115 STSs were unambiguously ordered, resulting in one ordered marker per 21 kb. The order of keratin type II locus genes was determined. This map would greatly enhance the positional cloning effort of the responsible genes for those diseases that are linked to this region, including male germ cell tumor as well as palmoplantar keratoderma, Bothnian-type, and triple A syndrome. This transcript map was localized at human chromosome 12q13.