Transgenic agriculture is new and raises special safety concerns2 Transgenic agriculture is new and raises special safety concerns2

The production of transgenic varieties - which features most prominently in genetic engineering agriculture - is a new departure from conventional techniques including selective breeding, mutagenesis (induction of gene mutations by chemical or physical means such as X-rays), cell fusion and tissue culture. It raises safety concerns different in kind from those of conventional techniques, and which are inherent to the processes used in creating transgenic organisms.

Typically, genes of one or more donor-species are isolated, and spliced into artificially constructed infectious agents, which act as vectors to carry the genes into the cells of recipient species.Once inside a cell, the vector carrying the genes will insert into the cell's genome. A transgenic organism is regenerated from each transformed cell (or egg, in the case of animals) which has taken up the foreign genes. And from that organism, a transgenic variety can be bred. In this way, genes can be transferred between distant species which would never interbreed in nature.

The artificial vectors are typically made by joining together parts of the genomes of natural viruses that cause diseases and other genetic parasites, plasmids (pieces of usually circular DNA found in bacteria and yeasts, replicating independently of the chromosome(s)) and transposons (mobile genetic elements, or 'jumping genes' found in all species), which carry and spread genes for antibiotic and drug resistances, as well as genes associated with diseases। Most, if not all of the disease-causing genes will have been removed from the artificial vectors, but antibiotic resistance genes are often left in as 'selectable markers', so those cells which have taken up the foreign genes can be selected with antibiotics। While natural viruses and other genetic parasites are limited by species barriers to varying degrees, the artificial vectors made by genetic engineers are especially designed to cross specie barriers and to overcome mechanisms in the cell that destroy or inactivate foreign DNA.

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