DNA, or deoxyribonucleic acid, encodes the biological instructions necessary for the development and function of all living things. It is known to be the instruction manual or blueprint for life. Recently, a new breakthrough in our understanding of DNA has emerged. Professor Romesburg and colleagues at the Scripps Research Institute in La Jolla, California have experimentally demonstrated that life can exist with information that is not coded in the way nature does it. Does this mean that DNA as we know it on earth may not be the only solution for coding life?
DNA is made up of four building blocks or chemical bases: adenine (A), cytosine (C), guanine (G), and thymine (T). It is the order or sequence of these building blocks that makes up the biological instructions for building and maintaining a living organism. Human DNA consists of 3 billion bases. DNA is shaped like a long ladder and wound into a spiral. This makes it well-suited for storing an incredible amount of biological information. An important property of DNA is that it can make copies of itself or replicate.
In their experiments to show that life can exist from DNA that is altered, Romesberg and colleagues added chemicals, called X and Y, to DNA. These are completely different from the four building blocks of DNA. After searching extensively, they decided to use the X and Y chemicals because of their ability to replicate well in a test tube. The scientists then inserted the chemicals X and Y into E.coli, a bacteria that easily accepts foreign DNA. They showed that the bacteria reproduced about 23 times, passing down the X and Y chemicals, and remained completely healthy.
Medicine can greatly benefit from this remarkable discovery. Proteins, made from the information stored in DNA, are an important source of drug therapies. However, because of the limited number of DNA building blocks, the proteins that can be made have also been limited. Now, scientists may be able to use this artificial DNA to create proteins that never existed before. These proteins may represent novel drug therapies.
Read about this and the next steps for Romesburg’s research here.