It’s been a little while I know but I’m slowly coming to the end of my course. I have new posts with new material coming soon but for now I thought I’d leave you with a little light reading while you wait…
DNA. These three little letters are the key to our genetic make-up. Our DNA is inherited from our parents and although it feels like it’s been around forever, it is only within the last 65 years that its structure has been discovered. Back in 1953, Francis Crick and James Watson co-discovered the double helix structure of the DNA molecule. A beautifully complex configuration which is utterly detrimental to our development as well as our health. Their discovery won them the 1962 Nobel Prize in Medicine alongside Maurice Wilkins and is still regarded as one of the major scientific discoveries of the 20th century.Born on 8 June 1916 in Northampton, Francis Harry Compton Crick studied Physics at University College London. This enabled him to work on the development of mines during the Second World War. However, once this was over he switched to biology and landed a job at Cambridge University in 1947. In 1949 he began working for the Medical Research Council in Cambridge which in 1951 saw the arrival of an American student named James Watson. This was the birth of a working relationship which would become fundamental across the world. I guess you could say they were the Lennon and McCartney of the science world.
At the same time there were another couple of scientists also carrying out research on DNA, Maurice Wilkins and Rosalind Franklin. Crick and Watson used Wilkins and Franklin’s research in their own investigations. This collaborative discovery of the helical structure of DNA enabled the advances in molecular biology we have witnessed over the last 63 years.
DNA is short for deoxyribonucleic acid and consists of three major components; a nitrogenous base, deoxyribose and a phosphate molecule. The backbone of DNA consists of two strands which cross each other to form the helical shape. These strands are made up of sugar and phosphate molecules with the sugar linking up to one of four nitrogenous bases; adenine (A), thymine (T), cytosine (C) or guanine (G). These bases pair up specifically for example A with T and C with G. This structure gives DNA its functionality in that it allows its replication to take place and it also allows information to be stored in the sequence of bases along each strand. It is this vital information which Crick and Watson were famous for discovering.
Our expanding knowledge of DNA has helped to pave the way for new technologies and advances. One of the most notable experiments carried out by researchers was Dolly the Sheep back in 1996. When you think of big science fiction stories many will think of cloning and the benefits which could arise from this. Well, Dolly was a perfect example of cloning and helped to highlight areas where cloning could be used. Dolly was produced through a process known as nuclear transfer. Put simply scientists took an udder cell from a white faced sheep and modified its growth medium to keep it alive but prevent it from growing. Once satisfied this cell was injected into a nucleus-free egg cell from a black faced sheep and these cells were fused using electrical impulses. Sounds simple doesn’t it? But Dolly was just 1 of 227 attempts to go full term. And only 29 of the 227 developed into embryos so maybe it was little bit more complicated than it sounds. The success of this experiment helped to pave the way for new advances within areas such as pharmaceuticals and agriculture. With regards to this advances have been made in human medicine whereby a new therapy has been developed which could potentially help to ward off mitochondrial diseases which are inherited from the maternal line. At present this treatment is not available for use in humans but it is promising for the future.
DNA doesn’t stop there over the last three decades the use of DNA and forensic technology has helped to solve some of the biggest crime investigations not only in the UK but throughout the world. During the emergence of DNA profiling a scientist first port of call was the analysis of the ABO blood groups. However, it was in 1985 that a breakthrough was made when the University of Leicester’s Sir Alec Jeffreys developed DNA based identity testing. Geneticist, Jeffreys was working on a project using seals and analysing myoglobin genes. It wasn’t until he and his team discovered short repeating sequences in these genes that they realised these could potentially be useful. In fact the team found that some of these sequences were also homologous with humans. Professor Jeffreys compared these sequences to those that had already been published and found they matched with these “mini-satellites”. In light of this the team developed a radioactive probe which could attach to these repeating sequences. This exposed sequences which were 100% unique to each individual and so the DNA “fingerprint” was born. In 1985 Jeffreys paper was published in Nature and ultimately led to the technology being used in both identity tests and criminal investigations.
So what’s next for DNA? Not only has it lent itself to breakthroughs in ID and crime but its future in medicine may also be promising with the development of personalised medicine. This will utilise the genetic knowledge gathered about an individual to help predict the development of disease or help physicians adapt treatment options for each individual or influence lifestyle choices. Potentially individualising medicine and healthcare. However, this approach is heavily reliant on new biotechnologies namely new advances in genetic testing. This data can then be interpreted by a healthcare professional. In many ways healthcare has always had an element of personalisation yet what sets personalised healthcare apart from standard approaches is its understood links to disease. Let’s face it the majority of diseases or illnesses are influenced by genetics in one way or another. Even though the role of genetics is assumed in the development and treatment of disease its full contribution can vary from single genes to a combination of both genetics and environmental factors. Yet regardless, personalised medicine demands that the genetic contribution is always respected.
Over the last 60 years the advances in biotechnology have not only enabled the discovery of the structure of DNA but we are approaching a period where DNA could eventually influence healthcare. The possibilities with DNA appear to be endless with its impact felt across a variety of mediums all contributing to the society we now live in and really it’s all thanks to the pioneers we know as Crick and Watson.