Mostly the bacteriophages attach only to a few kinds of bacteria. But they have a tendency to broaden their host range. Bacteriophage transduction is especially common in water. It has long been believed that mating or conjugation only occurs between members of the same bacterial species. Mating is mediated by a special small piece of DNA, the plasmid that is separate from the bacterial chromosome.
Most plasmids are also carriers of antibiotic resistance genes.
The plasmids are transferred at mating. Also a kind of jumping genes are transferred separately at mating. They can jump between different positions in the chromosome or between chromosomes and plasmids. Among these jumping genes there are a special kind of genes that support efficient transfer of antibiotic resistance genes. Conclusion Uptake of naked DNA, transfer by virus and transfer by mating all may contribute to uncontrolled spread of genetically engineered genes by microorganisms.