Six Nucleotide DNA Crafted in Living Organisms

Scientists created functional genetic information that contributes two additional letters to the natural four-letter genetic alphabet. Not only has this altered genetic information been accepted by organisms in labs, it has also been copied and carried over in natural cell reproduction.

The common scientific knowledge is that every living organism has four nucleotides - the chemical building-blocks of DNA - in its genetic code. Each of these nucleotides is represented by a different letter in science, being  A, T, C, and G.

However, according to a study published in the journal Nature, researchers have successfully crated "semi-synthetic" organisms that carry three different base pairs, or six nucleotides, in their genetic information. According to the study, researchers from The Scripps Research Institute, working with New England Biolabs, have now added the letter pair X and Y to the genetic alphabet.

But what would even be the benefit of having six nucleotides? Study author Floyde Romseberg of the Scripps Research Institute in La Jolla, Calif. told Wired that cells containing more genetic mutation can potentially create new proteins that nature has not even seen yet. This would then open up opportunities for researchers to "craft" proteins that can be useful in therapies, studies, and even new treatments for genetic disorders.

While we are still a long way from that dream becoming a reality, Romeberg's latest work has brought the scientific community a significant step closer.

According to the Nature study, Romesberg and his team managed to insert six-lettered DNA into E. coli bacteria through in vitro alteration and transcription.

The bacteria then divided into more microbes which were found to express the same DNA alterations -- indicating that not only can six-letter DNA be adopted by an organism's genetic structure, it can also be replicated through natural reproductive processes.

The study was published in Nature on May 7.