Final answer:
Plasmid genes are advantageous under conditions where bacteria need antibiotic resistance or the ability to degrade unusual compounds. They are also used in molecular cloning and genetic engineering to introduce foreign DNA and produce recombinant molecules.
Step-by-step explanation:
Plasmids are extra-chromosomal genetic elements found in bacteria, such as Escherichia coli, providing advantageous traits to the organism. Plasmid genes are particularly advantageous under special conditions that require traits like antibiotic resistance or the ability to produce antibiotics. This can be crucial in environments where antibiotics are prevalent, allowing bacteria with plasmids to survive and proliferate. Moreover, plasmids can carry genes that enable bacteria to degrade unique and complex compounds, which is beneficial in nonclinical environments polluted with substances like polycyclic aromatic hydrocarbons (PAHs).
In the field of biotechnology, plasmids have been engineered to serve as vectors in molecular cloning, facilitating the introduction of foreign DNA via a multiple cloning site (MCS). This has led to the production of important molecules like insulin. Plasmids can be manipulated using restriction endonucleases and DNA ligase to cut and join DNA fragments, allowing the creation of recombinant DNA molecules for various applications, including genetic engineering and the large-scale production of reagents.