“Hachimoji Alien DNA” – Genetic Code Expanded From Four To Eight
Guanine(G), Cytosine(C), Adenine(A) and thymine(T) are the four base pairs that form DNA – the hereditary unit of life on Earth. In a groundbreaking discovery, Researchers at the U.S have built an “Alien” Synthetic DNA that comprises of eight building block letters, expanding the genetic code of DNA from four to eight base pairs.
The researchers say that the new form of DNA meets all the Darwinian evolution rules and can also undergo transcription to form RNA. This study can revolutionize future synthetic biology research & its applications. Most interestingly this can solve the entangling mysteries on how to support life out of the earth – in space.
The above study has been published in the Science Journal on 22nd February, with the lead author of the paper being Steven Benner, founder of the Foundation for Applied Molecular Evolution in Alachua, Florida.
Understanding the novel Eight Building blocks of DNA
With the help of organic chemistry principles, four more building blocks were designed by the scientist in addition to the existing four base pairs, that resembles shape & size ratios of G:C and A:T base pairs and also bind with them. The new building blocks are, P & B – which
are analogues of Purine and Z & S – that are are analogues of pyrimidine. These duplexes form P: Z and B:S pairs.
The researchers decided to name their Alien DNA as “hachimoji” DNA – wherein “hachi” means eight in Japanese and “moji” letter.
Steven Benner explained that using this new synthetic genetic system, they have built several other molecules in order to study their binding ability to their complementary genetic molecules. This led to rules that predict how well a sequence of synthetic building blocks, say GACTZPSB, bind to a complementary CTGAPZBS sequence.
Hachimoji DNA Compared to Natural Human DNA
Researchers claim that the hachimoji DNA works similarly to natural DNA by supporting life as it pairs and makes copies of hachimoji RNA via transcription.
Benner said this new DNA system also comply with the Schrödinger requirement for a Darwinian system of molecular evolution – which states that in order to store information, a genetic material must have different building blocks, just like an alphabet must have different letters.
He further added that these extra – new nucleotide letters also can replace each other without geometrically disrupting double helical size or shape of DNA to support Evolution.
Hachimoji DNA Transcription Process
To aid the Hachimoji DNA in undergoing the transcription process – a natural enzyme (T7 polymerase) was used to ensure that it could accept unnatural genetic molecules. It is also one of the prime challenge faced while performing research with Synthetic DNA.
With the assistance of Andrew Ellington and his team at the University of Texas at Austin, T7 polymerase was designed that natural DNA to natural RNA by changing amino acids in the protein and finding ones that accept hachimoji DNA to make hachimoji RNA, added Benner.
Benner rejects the idea to call it an alien DNA as for that the system must be self-sustaining and hachimoji DNA needs a steady supply of the lab-created building blocks and proteins.
Future Applications of Hachimoji DNA
Multiple application areas of the Hachimoji DNA has been listed out by the scientist that includes self-assembling nanostructures, barcoding, development of clean diagnostics for human diseases, molecular information storage which can be retrieved and in the discovery of novel drugs.
Very Nice