GM Crops & Livestock
Biology: Cambridge International A Level, topic 19.3.1
Uses
Recombinant DNA has a variety of applications. These applications can be hugely beneficial in combating a number of humanitarian issues. These include:
Genetically modified crops
- Recombinant DNA can be used to genetically modify crops to improve their yield. This included crops such as maize, cotton, tobacco and oilseed rape.
- Traits that can be improved include -
- Resistance to disease.
- Tolerance to the application of herbicides and pesticides.
- Tolerance of adverse environmental conditions (e.g. drought).
Resistance to herbicides
- Genetically engineering crops to become resistant to herbicides can improve yields.
- Fields containing the resistant crop can be sprayed with herbicides.
- The herbicide will kill any competing weeds, but the crops will remain alive.
- The absence of competition from weeds will allow the crops maximal access to resources such as sunlight and soil minerals.
- So, the crop yield will increase.
Resistant to insects
- Genetic engineering can be used to produce crops that produce their own insecticides.
- For example, transgenic corn has been genetically engineered to produce an insect toxin.
- This toxin is called the bt toxin. So, this type of corn is sometimes called bt corn.
- The toxin is toxic to certain pests, so the pests avoid the corn.
- As the corn is not lost to pests, the yield of the corn increases.
Increased nutritional value
- Recombinant DNA can be used to increase the nutritional value of food.
- E.g. Rice has been genetically modified to contain Vitamin A (beta-carotene). Vitamin A is a common deficiency in Asian countries where rice is widely consumed.
Livestock
- Atlantic salmon have been genetically modified to produce greater yields of bigger fish.
- This has been done by inserting a DNA promoter for growth hormone into fertilised salmon eggs.
- The presence of the promoter leads to increased transcription of the growth hormone gene.
- The increased production of growth hormone means the fish reach maturity almost twice as quickly than in unmodified salmon.
Test yourself on GM Crops & Livestock
Which of these is a trait that could be improved in genetically modified crops?