What is Gene+c Modiﬁca+on?The conceptual foundation of biotechnology is not new.Man has been cross-breeding animals and hybridising plants toselect desired characteristics or to improve crop yields forthousands of years.
First GM plantsThe 20th century witnessed huge advances being made byscientists to unravel plant and animals genetic coding and foundnew ways to achieve in evolutionary terms a blink of an eye towhat may have taken hundreds or thousands of years to achieveusing conventional means.By the latter part of the last century scientists were able toidentify traits and the genes associated with them and transferthem from plant to plant.The first plant to be genetically modified was tobacco in the early90’s followed by herbicide resistant soy in 1995.
Gene+c TraitsGenetic modification is expensive and involves scientistsidentifying the genetic traits which might be of use. The sourceof genetic information known as DNA often comes from plants orbacteria but could come from animals.The genes selected are often responsible for producing traitswhich confer tolerance to pesticides, produce chemicals toxic toinsects, help plants resist diseases or alter the nutritional valueof the plant.
Copyrights and PatentsBiotechnology companies, government bodies invest vast sums of moneyon research to screen organisms for useful traits and identify the genesresponsible for them.Biotechnology companies patent their discovery in the event that royaltiescan flow from use of the genetic code . Because genetic modification isexpensive, biotech companies vigorously protect their copyright andintellectual property.
Gene+c Modiﬁca+on ‐ Step 1Scientists must first identify and isolate the genes responsible for thedesired trait and then create a genetic cassette containing the targetsequence and additional pieces of DNA taken from other plants,bacteria or viruses called marker genes.These marker genes (promoters and terminators) flank the targetsequence and act like biological on and off switches for the cell so thatthe host plant will produce the desired protein responsible for the trait.A promoter (35Sp) from the cauliflower mosaic virus is commonly usedbut other genetic material from plants may be used instead.
Gene+c Modiﬁca+on ‐ Step 2Two methods have been developed to insert the genetic cassettecontaining the desired sequence into plant cells.The first method uses an ubiquitous bacterium, Agrobacteriumtumafaciens like the Trojan horse because it has which has the ability toinfect plants and insert its (and the new genetic information) into thehost plant’s DNA.The second method known as ‘biolistics’ because tiny fragments of goldor tungsten carrying the new genetic information is fired into the plant’scells.
Gene+c Modiﬁca+on ‐ Step 3Because of the randomness of both insertion techniques success ratesare low because scientists cannot control where in the plant’s genomethe cassette is inserted nor how many copies are inserted.Many thousands of plant are then cultivated and screened todetermine if the desired trait has made it into the host plant’s genome.To achieve this, scientists are helped by the marker genes one ofwhich may confer for example antibiotic resistance.
Gene+c Modiﬁca+on ‐ Step 4Scientists then test the mature plants to determine that the desiredtraits work and that the trait is passed on following conventionalMendelian inheritance.
Gene+c Modiﬁca+on ‐ Step 5Official authorisation is required to move onto greenhouse trials andthen outdoor field trials.If these trials are successful a commercial variety which includes theGM trait is then produced. Further field trials then follow to ensure itperforms well and as expected in the environment.At this stage the biotechnology company may apply for EU approvalto release the crop commercially and requires the submission of adossier of evidence containing covering food and environmental risk.
Regula+onThe EU regulatory system assesses the genetically modified cropwith its non-genetically modified equivalents with respect to chemicalcomposition a process known as ‘substantial equivalence’.The EU system is superior to other systems in other parts of theworld which often heavily rely upon data being provided by the verysame biotechnology company seeking approval.
Gene+c Modiﬁca+on of animalsGenetic modification of animals is similar in most respects howeverthe new genetic material must be inserted into embryonic stem cellsusing micro-injection or a virus.The genetically modified animal must then be cloned to ensure theinserted trait is passed on to the next ‘generation’.