BAC Library Construction And Physical Mapping Of Bacillus Anthracis A16R

Bacillus anthracis is an endospore-forming bacterium that causes severe inhalational anthrax. Bacillus anthracis A16R is an attenuated strain derived from Bacillus anthracis A16 .The development of bacterial artificial chromosome (BAC) system has allowed the construction of large insert-size DNA libraries, and the Bacterial artificial chromosomes (BACs) have become the preferred large insert cloning system for genomic analysis because such libraries are characteristically stable, show high fidelity, and easy to handle. To facilitate genome studies of this bacterium, a bacterial artificial chromosome library (BAC) has been established from genome DNA of Bacillus anthracis A16R .This library consists of 9600 clones randomly selected from more than 15000 recombinant clones carrying inserts in the plindigoBAC-5 vector. The mean insert size was 56kbp, representing an approximate 12-fold genome coverage . End sequences were obtained from 700 randomly selected clones .Sequences were compared to the Bacillus anthracis Ames and Bacillus cereus ATCC 14579 Genome Project databases using the NCBI BLASTN search project. Most BLASTN results showed high identities and the sequences' sites can be used as STSs. To construct this physical map, Excel was used for the array of STSs and some gaps of the map were filled up by PCR walking. Artemis-V4 was used in the construction of a genome-wide physical map with 93% genome coverage. The A16R BAC library proved to be a vital tool for the generation of a map that will not only allow the subsequent sequencing of defined areas of genome , but also provide immediate access to clones that are stable and convenient for functional genomic researches.