Research Highlights 



Instrumentation and methodologies, being developed to use multiple stable isotopes 

 as DNA labels for mapping and sequencing tasks, will increase the speed of sequencing. 



Chemiluminescent techniques for displaying DNA fragments are now achieving 

 .sensitivities of radioisotopic labels, with promise for reduction in safety hazards and 

 hazardous waste disposal costs. 



The first nondestructive images of naked DNA have been achieved through scanning 

 tunneling micro.scopy and provide promise for single-molecule DNA sequencing. 



A multiplex walking strategy has been applied to an 1 100-member library 

 representing chromosome segment 1 Iq. Automated restriction mapping is now being 

 utilized to confirm/reject the presence of overlaps between cosmid pairs with 

 homologies. Some 300 contigs have thus far been constructed. 



An automated fluorescence-based method for clone fingerprinting has been 

 developed, validated, and coupled to software used for contig assembly, data storage, 

 and graphical display of map infomiation. These procedures are being successfully 

 applied toward the development of a cosmid and YAC contig map of human 

 chromosome 19. 



A new method of genome mapping using human-specific repetitive sequences and the 

 polymerase chain reaction {Alii PCR) has been developed. This method is used for the 

 isolation of regionally localized DNA fragments and for the rapid and efficient 

 characterization of cloned DNAs, particularly those in YAC vectors. 



28 



