Production of LMOs through genetic modification is a multistage process that can be achieved through a variety of methodologies. Methods commonly used in the development of LM plants can be summarized as follows.
Once a gene of interest has been identified and isolated from a donor organism, it is manipulated in the laboratory such that it can be inserted effectively into the intended recipient organism. The manipulation may, for example, include changes to the sequence of nucleotides so as to enhance or modulate the expression of the gene once it is introduced into the intended recipient organism.
One or more genes of interest, as well as other nucleotide sequences needed for the proper functioning of the gene(s) of interest, may then be built in an orderly sequence into a “gene construct”. The gene construct typically includes a “promoter sequence” and “termination sequence” which are necessary to ensure that the gene is expressed correctly in the recipient organism. Different promoter sequences control gene expression in different ways; some allow continuous expression of the gene (these promoters are known as “constitutive”), while others switch expression of the gene on or off at different tissues, organs and/or developmental stages of the organisms or in reaction to other external influences. Some promoters may be highly specific to the point that they drive gene expression only in a few cells of the organism and during short, specific developmental stages.
A “marker gene” is often incorporated into the gene construct to help identify which individuals of a recipient organism have been modified by the introduction of the gene construct.
Finally, the gene construct may be incorporated into a larger DNA molecule to be used as vector (e.g. plasmid, virus, etc.). The purpose of the vector is to assist the transfer of the gene construct into the recipient organism.
