Molecular Analysis from Xq27.3 to Xqter
We propose to complete the establishment of overlapping clone libraries of the end of the long arm of the human X chromosome, the region between the position of the fragile site & the telomere, & to compare the structure of the region to that in the mouse. The size of this region as determined by pulsed field gel analysis is between 8.5 to 9.5 megabases (Poustka et al., 1991). This area has the highest density of mutations associated with human genetic diseases and has therefore been analysed intensely in a number of laboratories by different techniques and large amounts of information and resources have been generated. This region can thus serve as a prototype for the further analysis of larger regions of the human genome. In previous work we have constructed overlapping clone coverage of a major fraction of this area, based on the integration of YAC, cosmid & linking clone contigs. In extension to this work we propose to close the remaining gaps in the YAC clone coverage by hybridization of additional probes to YAC filter grids of additional YAC libraries (which have not been screened yet). As yet unassigned cosmid and linking clone contigs will be positioned on the physical map of the region by hybridization of Alu PCR products of gel-purified rare cutter restriction fragments to the gridded clone libraries (Poustka, A., 1991). To complete the complementary coverage of the entire region in bacterialcloning systems,we will screen high density filters of a cosmid library of the entire X chromosome and a P1 library of the entire genome. In parallel, we plan to construct a complementary coverage of the region in mouse YACs, to allow a detailed comparison of this region in these two species and easy access to conserved sequences.
nis work will complete the clone coverage of Xq28 in both yeast & bacterial cloning systems, and will serve as the basic material in the establishment a gene and transcriptmap of this area, and the determinationof the complete genomic sequences of this region, planned in collaboration with the groups of John Sulston (sanger Institute, Cambridge, UK) and Andre Rosenthal (Jena, Germany), as well as other groups in the US and Europe.
Funding SchemeCSC - Cost-sharing contracts
WC2A 3PX London