text: PAC is commonly used as a large capacity vector which allows propagation of large DNA inserts in Escherichia coli. This feature has been commonly used for:
  * building genome libraries for human, mouse, etc, helps with projects such as Human Genome Project
  * libraries served as the template for gene sequencing (example: used as gene template in mouse gene function analysis)
  * genome analysis on specific functions of different genes for more complex organisms (plants, animals etc.)
  * facilitate gene expression
  Since PAC was derived from phages, PAC and its variants are also useful in the PAC-based phage therapy and antibiotic studies.