GE Plants

As an example, let us see how GE soya was generated. The objective here was to introduce into the soya plants a gene from a common soil bacterium which would allow it to survive when sprayed with the herbicide Roundup. Clearly you cannot “cross” a bacterium with a plant. Therefore, the first step was to grow cells from soya bean plants on plastic dishes in the laboratory. Now, in order to allow the bacterial gene to be able to work once introduced into its new plant host, it had to be linked to a genetic switch combining parts from a cauliflower virus and petunias. (As we discussed above, the bacterial gene’s own switch will only work in the bacteria from which it came). This combination of cauliflower virus, petunia and bacterial DNA was then introduced into the soya bean cell growing on the dished in the laboratory. Most of the cells don’t take up the DNA. This is done using a genetic trick. The introduction of the bacterial gene into the soya bean cell for herbicide resistance was accompanied by a second gene which confers resistance to an antibiotic. The soya bean cells were then treated with the antibiotic. The few cells which had taken up the herbicide resistance: antibiotic resistance “maker” gene combination survived and flourished whereas the majority of the cells which had not taken up these genes were simply killed by the antibiotic.

Finally, by changing the conditions under which the soya bean cells are grown, the cells clump together to form what is called a callus which in turn starts to put down roots and sprout green shoots. They are planted to grow into fully mature plants, the plant which displays the best agronomic performance, in this case resistance to herbicide, is then selected for further development.

Another example which illustrates the extreme combination of genetic material that can be produced is the introduction of the “anti-freeze” gene from an arctic fish into tomatoes, strawberries and potatoes in hope of producing resistance to frost.