During the 20th century, DNA became one of the most essential discoveries ever made. This discovery has meant that we can improve the diagnosis of certain diseases and we have even been able to identify certain genes that cause diseases. We can use DNA to identify unrecognisable bodies, find the identity of a criminal from a crime scene from even one strand of hair that contains DNA resulting in the successful prosecution of them. Furthermore, the paternity of a child can be determined through DNA, meaning that parents can identify the correct father to a child. We can make it so that medication can be modified to one person as an individual, also if the medication is safe for that individual to use. We can create clones of animals, just from replicating the DNA.DNA, or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms. DNA is located in the cell nucleus, and the information in DNA is stored as a code made up of four chemical bases- adenine, guanine, cytosine, and thymine. Human DNA consists of about 3 billion bases, and the order of these bases is what determines the information that they give for building and maintaining an organism. An important property of DNA is that it can replicate itself, each strand of DNA in the double helix can serve as a pattern for duplicating the sequence of bases. This is important as when cells divide, each new cell needs to have an exact copy of the DNA present in the old cell.DNA is used in science on a daily basis, in order to study genes via genetics, it has helped scientists to understand the sequence of DNA in human cells which has provided the possibility to identify every individual. An in depth study has proven that every individual has their own unique genes, which means that everyone can be identified by a piece of their blood, a strand of hair, semen and even a drop of saliva. This has been revolutionary in the aspect of forensic science as even the tiniest piece of evidence can place someone at a crime scene. The human genome project was a reveloutionary project in DNA study. The project discovered more than 1800 disease genes, as a result of this todays reserchers can find a gene suspected of causing an inherited disease in a matter of days, rather than the years it took before the genome sequence was in hand- consequently, this is saving the government millions of pounds in research. Furthermore, medication can be modified to suit a certain individual, alongside being tested to see if the drug would have a negative effect on the patient. This means that instead of the 13 years on average that it takes to develop a drug, it could be done in months without such a high cost with a higher success rate. In the past, drugs that have been successful for many patients have had catastrophic effects on a small number of people- resulting in it being completely cut off. For example, thalidomide was a drug used for easing morning sickness for pregnant women and as a sleeping tablet in the 1960’s which was beneficial to millions of people, however this caused many babies to be born with malformed limbs. The drug was completely cut off from the public, however due to this testing it has been found that the drug has been very successful in treating conditions such as myeloma and leporacy, and now that it is known that this drug is not safe for pregnant women, babies with birth defects as a result of this drug can be prevented. All of our genetics are different, we are all individuals and therefore certain drugs will affect everybody in a different way, however in the past if the minority have a bad reaction to a drug it will be taken completely off the market, meaning that the millions that could have been helped will go without. A prime example of this was the drug vioxx, a painkiller used to ease the symptoms of arthritis in order to make life livable again, however in certain cases the drug caused heart issues such as heart failure. Using stem cells, cardiac cells could have been taken from the patients and the drug could have been tested to see if it would be successful, and what the side effects would be, and for those who had no negative effects, they could have taken the drug to ease their symptoms and this would mean that the years and money that went into producing the drug would not have gone to waste like it did. Recombinant DNA technology is DNA molecules formed by laboratory methods of genetic recombination such as molecular cloning to bring together genetic material from different sources, which creates sequences that would not otherwise be found in the genome. To begin with, the specific gene is isolated and copied. Then the gene will be placed inside a vector, for example a plasmid, which will carry the gene to the target cell. The recipient cell will then have recombinant DNA and will express a newly acquired gene. This process involves the manipulation and combination of genes from different organisms, it works because the genetic code is universal and transcription and translation occur by the same mechanism across organisms. This is beneficial as this process can achieve the production of human insulin, without the extraction of it from another animal. Non human insulin can cause allergic reactions, which can cause many different complications on its own. Having human insulin made in a laboratory would mean that mass production could occur, without the use of animals and without the reactions from certain patients.To conclude, DNA is a molecule that consists of genetic instructions, which are used in the growth, reproduction, function and development of all living organisms. DNA has become essential in modern day life and has been used in multiple fields such as science and technology, scientists have been able to discover how the genes of humans, animals and plants work, and have even been able to use DNA to detect and treat against certain diseases such as cancer. DNA has given us an understanding of how the human body works and how every individual reacts in a different way to different drugs as a result of our genetic code, which we have already been able to use to modify the way we treat people, and in the future there will be plenty more to discover to possibly prevent diseases such as alzheimer’s and maybe even cancer in the same way they did with polio.