Next, the gene is spliced into a vector to make protein. A vector is a gene carrier which will carry a human gene into a bacterium. Plasmids are often used as vectors. They are short circular strands of DNA found in some bacteria. The joining process is controlled by the enzyme ligase and is called ligation. The new circular DNA molecule produced is called recombinant DNA as it contains genes from the original plasmid and the human gene.
Finally if to discover if the uptake of DNA had been successful a gene for antibiotic resistance is used. If bacterial cells have successfully taken up the recombinant DNA then it will be resistant to the antibiotic. They are then grown in fermentors. Cells that have not taken up the DNA will be killed by the antibiotic. (3)
Recombinant DNA technology has many different uses. It is used for genetically engineered micro organisms. This is when human genes are inserted into bacteria which are then grown in fermentors. The bacteria then produce a human protein. So, large amounts of insulin and human growth hormone can be produced cheaply.
It is used to map human chromosomes (The human genome project). The aim of this is to create a map of all the human chromosomes identifying the precise location of every gene. This will help to develop a new gene therapy treatment
It can be use for identification of mutations-people may be tested for the presence of mutated proteins that may be associated with breast cancer, retinoblastoma, and neurofibromatosis.
It can be used for Diagnoses of affected and carrier states for hereditary diseases -Tests exist to determine if people are carriers of the cystic fibrosis gene, the Huntington’s disease gene, the Tay-Sachs disease gene, or the Duchenne muscular dystrophy gene.
It is used for genetically modified animals- Human proteins such as haemoglobin and blood clotting factors are already produced in the milk of transgenic cows, goats and sheep.
It is also used for genetically modified plants- Desirable genes can be transferred from an organism to a crop plant. His could make crops more useful as it will improve resistance to pests and bacterial, fungal or viral diseases. It will enable plants to resist cold or drought and it will improve storage time.
However despite safety checks, may people are concerned about the risks of recombinant DNA technology. Here are some of there moral or ethical concerns. Genetically modified crops could escape- If pollen or seeds were carried from test plots they might result genetically modified populations elsewhere. A genetic modification could involve resistance to herbicides these plants could become super weeds that we could not control.
Population of transgenic organisms could upset the balance of nature- Populations of transgenic salmon have been produced in which individuals grow rapidly. These transgenic fish could compete for food with other species. The latter could become extinct and natural food webs could change.
Eugenics-Genetic engineering could be used to insert genes into humans. In some cases this process could prevent early death. However, in others it could be used to give individuals characteristics that are considered to be desirable. This is unacceptable to many people.
Objection to specific transgenic organisms- Many religious groups could not use products from specific organisms
Finally screening could lead to discrimination against individuals-When fetuses are screened for genetic disorders, parents often face a dilemma about aborting affected fetuses. It will become possible to screen adults for genes that predispose them to genetic disorders. This might lead to insurance companies discriminating against people with these disorders, even though they have perfect health.(2)
In conclusion recombinant DNA technology can help many people by stopping illness but this process has also been vandalised for many uses which are not necessary. For example it could be used to give individuals characteristics that are considered to be desirable. This reminds some people of some of the programmes that have been used throughout modern history to eradicate less powerful ethnic groups. Also this treatment may stop genetic disorders but this could lead to everybody being cured of illness. Therefore if people don’t die of the genetic disorders the world would become over populated.
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- AQA Biology by Martin Rowland
