An organism which carries or transmits a pathogen; a vehicle that transfers genetic material into a host cell or organism. Typically, vectors are of two types: viral- or DNA-based. DNA vectors are automously replicating, circular macromolecules that can be easily manipulated to carry genetic information and are transferred into cells by standard laboratory techniques. These vectors include plasmids, cosmids, and yeast artificial chromosomes (yacs). Recombinant viruses that have been bioengineered to be harmless can also carry new genetic information for transfer into cells, or into an entire host organism (an example of gene therapy) .