One of the most recent and interesting developments has been Genetic Engineering. Due to a lack of sophisticated equipment and technology in previous years, studying the gene in depth was impossible. A revolution in modern biology occurred in the years 1971 – 1973, which allowed genetic research to make great advances. Today, genetic engineering and gene cloning is allowing for progress in medicine, industry and agriculture. As gene cloning progresses, scientists are ever increasing their hopes for finding cures for diseases which were once thought to be incurable. With exciting recent breakthroughs in the cloning of animals, such as Dolly the Sheep, genetic engineering is once again in the middle of a ground-breaking revolution. Genetic engineering has many benefits, one of which is allowing people to breed animals with the best features. This can be done by extracting genes from one organism and inserting them into another. A recent break though which hit the headlines was cloning Dolly the Sheep. This was done by a scientist removing the nucleus from one of Dolly’s unfertilised eggs with a micropipette, and removing the nucleus from a donor cell from her liver. The nucleus from the donor cell would then be inserted into the target cell (her liver cell). The newly fertilised egg would then be placed in a surrogate sheep to grow, and a clone of Dolly would be produced.
However, genetic engineering can also be performed in plants, so only those plants with the best features, such as higher yield and better taste, will be used. Desired genes can be placed into plants using Agrobacterium as a vector. The bacteria Agrobacterium is able to infect over 1000 species of broad-leaved plants, entering by wounds. The bacteria carry a Ti (tumour inducing) plasmid. The plasmid DNA enters the plant’s chromosome and stimulates the production of substances which produce a disfiguring tumour on the plant known as a crown gall. However, the Ti plasmid can be used to introduce genes artificially, by being removed from the Agrobacterium. The Ti gene would then be removed from the plasmid and a desired gene would be cut from a donor organism. The desired gene would then be inserted into the plasmid, which the Ti gene was removed from. The modified plasmid would be placed in a dish containing leaf discs, which the Agrobacterium is able to infect. However, this time the Agrobacterium does not contain the Ti gene, but instead holds a desired gene. The leaf discs produce transgenic plantlets which then grow normally.
The Agrobacterium system has been used to transfer a number of single genes into a range of crop species. Examples are crop resistance to herbicides, manipulation of crop height to stop long wheat blowing over in the wind, and to aid mechanical harvesting. Manipulation of ripening tomatoes is also a good example of how the Agrobacterium system has been useful. In order to reach the shops in a ripe state, tomatoes have traditionally been picked while green, being left to develop in transit on the way to a supermarket for example. However, this results in loss of flavour and many fruits go to waste because they are mushy and over-ripe. Researchers have managed to modify tomato plants by inserting a gene, which stops the ‘ripening’ gene from working at the normal rate. This means the tomatoes can then be left for longer on the plant until they are ripe and ready to be picked. They soften more slowly, suffer less damage and have a longer shelf life, which avoids waste.
Genetic engineering has also helped thousands of us who are diabetic and don’t have any insulin to control the sugar level in the blood. Human insulin can be made using genetic engineering techniques, which can then be used by diabetics. This is done in a similar way to most of the techniques highlighted above.
Biology has made a huge difference to many people’s lives, especially recent break- throughs and advances. I’ve only covered a very small part of genetic engineering in this essay, as there is much more. If things continue to be discovered, the lives of the dying and starving could be saved, and more criminals could be caught with forensic techniques. Biology really is the science of the future, as there have been so many recent break-thoughs, with the strong hope of many more to come.
