The whole genome shotgun technique used by Celera to decode Drosophila melanogaster and other genomes has several phases. The first phase involves the creation of libraries of the complete DNA of an organism that is shredded into small fragments. DNA used to make the Drosophila melanogaster libraries was provided by the Berkeley Drosophila Genome Project (BDGP). The second phase uses high-speed sequencing machines from Applied Biosystems to decode these fragments. In the third phase, the sequenced fragments are assembled into their proper order using computers employing sophisticated mathematical algorithms developed at Celera. After the shotgun sequencing phase is complete, a number of gaps inevitably remain in the sequence. These gaps are typically due to the inefficient cloning of certain fragments into bacterial vectors. These gaps are closed using a number of different molecular biology techniques. This fourth phase, often referred to as finishing, was done in collaboration with the BDGP. The fifth phase is the analysis and annotation of the genome, the results of which are available in the Celera Discovery System™