area of chromosome 4. Various mapping techniques have been used to begin mapping 

 around this area. 



Method under development for testing single fluorescent molecules in flowing 

 streams. Based on a new theory for optimizing fluorescence detection, an instrument 

 has been developed for measuring single molecules of phycoerythrin. This single 

 molecule detection (SMD) system can measure concentrations three orders of 

 magnitude lower than conventional fluorescence detection systems. The SMD system is 

 now being applied to the optimization of fluorescence detection of DNA fragments on 

 sequencing gels. 



Future Directions 



• Develop methods for microsurgical dissection of single DNA molecules and PCR of 

 fragments for direct mapping and sequencing. 



• Implement a chromosome-2 1 database pilot project to facilitate cooperation among 

 different groups and obtain user feedback on desirable or necessary features. 



• Complete an ordered library of chromosome 21 by second-generation methods. 



• Extend the size range of PFG to allow much higher resolution in the I- to 10-Mbp 

 range and separations of even larger DNAs. 



• Increase the sensitivity of imaging techniques for chromosome in situ hybridization. 



• Develop applications for robotics in laboratory procedures such as screening 

 libraries for linking clones and PCR analysis of sliced gel lanes. 



• Develop imaging techniques for direct sequence reading by scanning tunneling 

 microscopy (STM) or atomic force microscopy ( AFM). 



• Incorporate direct-imaging plate technology into automated protocols. 



• Develop efficient, versatile algorithms for searching and matching strings in 

 databases. 



• Extend data thesaurus techniques of consistent naming and prototypes to store, 

 index, search, and retrieve genetic map information. 



• Automate genetic stock centers to conduct pilot studies for acquisition, evaluation, 

 maintenance, and distribution of clones and associated data. 



For more information on the LBL Human Genome Center, please contact 

 Charles R. Cantor, Director, at (415) 486-6800 or FTS 451-6800. 



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