In this debate I will explain how recombinant DNA technology works its advantages and its disadvantages, I will then draw a conclusion from the evidence and knowledge that I have gathered.
Stuart Norris Page 28/04/2007
Recombinant DNA techniques and our society
In this debate I will explain how recombinant DNA technology works its advantages and its disadvantages, I will then draw a conclusion from the evidence and knowledge that I have gathered.
Deoxyribose nucleic acid or DNA has been modified through selective breeding, artificially since man started to breed plants and cattle. We can now take the DNA of one organism and place it into another, giving the new organism advantages for example resistance to herbicides or pesticides.
This is done by very complex techniques. Firstly we need to find the gene that we will be coding for. We do this by using a probe, a shorter single stranded length of DNA; this carries the base pairing for the DNA that we are looking for. The probe is labelled with a fluorescent or radioactive marker. When the marker is added to the DNA under the correct conditions, the probe will attach to its complimentary DNA therefore showing where the needed DNA is.
This can then be cut from the chromosomes using an enzyme called restriction endonucleases. There are a number of types of enzyme that do this, however each cut the DNA in a different place this is known as the recognition sequence. The enzyme cuts the DNA in a specific way to give it “sticky ends” this means that it will bind onto the new DNA of the vector and new cell, when it is placed in the right section.
Once we have the gene we want to splice into the new cell we need a vector. For a vector we use a plasmid or bacteriophages because this replicate quickly and are easy to work with (all living organisms have the same type of DNA.). To put the human DNA in to the vector we must cut the section of the human DNA out using the probes and then use a vector which will accept the new DNA in to its chain. This is called ligation and is controlled by another enzyme called ligase.
From this the DNA is ready to be introduced into the host cell. There are several successful methods of doing this, the most common is to soak the bacteria in ice cold calcium chloride containing the recombinant DNA plasmoids this will make then produce a ligation. When this is done the vectors contain the human gene and therefore are transgenic organisms.
Despite what method we use to do this it the vector will not soak up all the plasmids therefore we need to remove the useless bacteria so we infect them with something that the vectors with the plasmids are immune to. This will kill the useless bacteria and leave the useful bacteria.
After doing that we need to culture the cells. This is very unreliable and only a small percent survive the culturing. On an industrial scale the vectors are fermented in large fomenters (conditions are carefully monitored.). Even if the vector has the new gene there is no guaranty it will be accepted in the new cell.
From this stage the vectors can be inserted in to the new host where the vector will penetrate a cell. From this penetration the spliced strand of DNA will combine with the old DNA. After the 2 sets of DNA have combined then the new cells eventually starts mitosis. This therefore increases the amount of spliced DNA in the body. This is useful when the vectors are viruses, however when creating insulin the bacteria is preferably used because it multiplies quickly.
