Abstracts: 

 Physical Mapping 



Mapping and Ordered Cloning of the Human X 

 Chromosome 



C. Thomas Caskey. David L. Nelson, and David H. Ledbetter 



Department of Molecular Genetics, Baylor College of Medicine, Houston. TX 77030 



(713)798-4773 



The ultimate goal of this project is the isolation of a complete set of overlapping DNA 

 clones comprising the human X chromosome. This goal will be achieved through 

 several means. A high-resolution pulsed-field gel map of regions of the chromosome 

 will be developed: the regions will begin in Xq28 and extend toward the centromere, in 

 order to assist in placement of clones as they become available. An extensive panel ot 

 somatic cell hybrids will be developed to assist in probe isolation and assignment. 

 Rapid isolation of novel X-region-.specific fragments will be achieved through the 

 development of a method based on the polymerase chain reaction human-specific AIn 

 primers for specific amplification of human sequences from somatic cell hybrid and 

 cloned DNAs will be utilized. Yeast artificial chromosomes retaining large X-region- 

 specific fragments will be utilized for regional isolation and overlap. Finally, a 

 computer database management system will be designed to assist in data handling for 

 these tasks. Initial efforts will focus on the Xq24-qter region with specific emphasis on 

 Xq28, a region with a large number of genetic disease loci. 



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