Using a tool called P[acman], group of researchers has established a library of clones covering most of the genome of Drosophila melanogaster (fruit fly), an organism widely used in genetics research.

P[acman]- developed by Dr. Koen Venken (http://flypush.imgen.bcm.tmc.edu/lab/koenv/index.html) in Bellen's laboratory- allows scientists to study large chunks of DNA in living flies. The vector - officially P/phiC31 artificial chromosome for manipulation - combines different technologies: a specially designed bacterial artificial chromosome (BAC) that allows maintenance of large pieces of DNA in bacteria, recombineering that allows the manipulation of large pieces of DNA in bacteria, and the ability to insert the genomic DNA into the genome of the fly at a specific site using phiC31-mediated transgenesis.

Venken adapted the P[acman] vector to create genomic libraries, so that a researcher can choose a gene and find the corresponding clones in the library that cover that gene. Their collaborators at Lawrence Berkeley National Laboratory, Drs. Roger Hoskins and Joseph Carlson, played a key role in the design, construction, and annotation of the libraries.

"You can insert a single copy of a gene and rescue a mutation, or do a structure/function analysis of the gene," Bellen said. "If you don't know where the gene is expressed, you can tag it, put it back and locate where it is expressed."

The new libraries are described in detail in a paper recently published in Nature Methods. The library is available at http://pacmanfly.org/.