The process of genetic engineering fundamentally differs from conventional breeding. During selective breeding, practiced by farmers for thousands of years, closely related organisms are crossed through a process that occurs in nature, such as sexual reproduction. Genetic engineering can take the genes of any living organism and add them to the DNA of any other living organism. This means, for the first time, genes from plants, animals, fungi, and bacteria can mix together bypassing all evolutionary and biological barriers. Because the technology of genetic engineering is both new and ground breaking, there is still a lot of uncertainty in the process of inserting new genes and in our understanding of how those genes are expressed.
Gene insertion is the process of putting a foreign gene into an organism.
A gene transfer requires a mechanism to carry the desired DNA into the host organism. This mechanism is called a vector. The most common vectors are viruses because they can attack a potential host cell s DNA and insert the selected genes. Alternatively, a gene gun shoots microscopic gold bullets coated with foreign DNA into the host cell. As a result, scientists often add antibiotic resistance genes along with the new genetic material to provide a test for the success of the gene insertion.