Humans have sought to control genes and to exploit genetic variation for thousands of years. Selective breeding has been used to modify the characteristics of plants and animals to better suit our needs. Examples are disease resistant plants, or cattle that give high yields of milk. But there are problems with this, since future generations of selectively bred organisms will share increasingly similar genes." During the twentieth century, scientists began to understand genes and genetics more deeply than before. Knowledge has reached the point where it is now possible to identify a gene for... Show more

Humans have sought to control genes and to exploit genetic variation for thousands of years. Selective breeding has been used to modify the characteristics of plants and animals to better suit our needs. Examples are disease resistant plants, or cattle that give high yields of milk. But there are problems with this, since future generations of selectively bred organisms will share increasingly similar genes."

During the twentieth century, scientists began to understand genes and genetics more deeply than before. Knowledge has reached the point where it is now possible to identify a gene for a particular characteristic and transfer it artificially into an organism. This is called genetic engineering and it allows genes to be transferred from the same species or from different species.

Some examples of genetic engineering are:

• Adding the carotene gene from carrots into rice so that people lacking vitamin A in their normal diet can make it if they eat genetically modified (GM) rice.
• Adding a gene from weedkiller resistant plants into soy beans. This means the farmer can spray their crop with weedkiller and only the weeds will die, meaning there is less competition and the yield of soy will be increased.
• Adding the insulin gene from humans into bacteria, meaning that insulin can be produced rapidly and cheaply to treat diabetics.

There are many ethical issues surrounding human control of genes by genetic engineering, and plenty of health worries too. Since the science is new, no-one knows what the long trem effects on the health of people eating genetically modified (GM) crops or animals will be. There are also religious objections because it seems like scientists are 'playing God'. 

Show less