Our DNA is basically made up of four building blocks of the DNA: adenine (A), cytosine (C), guanine (G), and thymine (T). Recently, however, scientists added two more synthetic nucleotides into the DNA making the total number to six.
Scientists from the Scripps research institute who authored the paper reported that being able to create a semisynthetic organism that carries the six-letter DNA code suggests that all processes of life can be manipulated.
The quest to add two new nucleotides to the four basic building blocks of the DNA began in 2014. The scientists first embedded the new nucleotides, X and Y, into the genetic code of an e.coli bacteria. However, when the cell began to divide, the bacteria was unable to hold on to the new genetic codes and died afterward.
Floyd Romesberg, one of the researchers, said that in order for the semisynthetic organism to become a real organism, it has to be stable enough to maintain the information it carries. Moreover, its genome needs to be stable for the rest of its life cycle just like all other organisms.
In order to do that, Romesberg and his team modified the nucleotide transporter to transfer the synthetic base pair to the cell. After that, they have to modify the Y building block so that the enzymes that synthesize the DNA will be able to recognize it and cause it to replicate. Lastly, the scientists used the CRISPR-Cas9 gene editing tool to give the e. Coli bacteria the ability to protect itself.
Through the process, the team was able to solve the problem at the fundamental level. The new organism considers any genetic sequence without the X and Y as threats while those with the X and Y blocks survive. Moreover, the new organism was able to replicate itself 60 times.
The researchers wrote in the paper that this paves the way for efforts to add more functions and forms to life forms. However, this process will still take a long time before it can even become practically applicable in real life.
