The Earth may have a dizzying array of life forms, but our biology ultimately remains a lone data point – we simply have no reference to life based on DNA that is different from our own. Now scientists have taken things into their hands to transcend the boundaries of possible life.
The NASA-funded research led by the Foundation for Applied Molecular Evolution in the US has led to the creation of a whole new taste for the DNA double helix, one that has four additional nucleotide bases.
It is called hachimoji DNA (from the Japanese words for "eight letters") and contains two new pairs that contribute to the existing partnerships of adenine (A) with thymine (T) and guanine (G) with cytosine (C). should be added. [1
Well, in a case that appears like a case of overachieving, researchers have once again focused on developing even more non-standard nucleotides.
However, they serve to double the number of codes in the recipe book.
"Through careful analysis of the roles of shape, size and structure in hachimoji DNA, this work extends our understanding of the types of molecules that can store information in extraterrestrial life on extraterrestrial worlds," says chemist Steven Benner.
We already know a great deal about the stability and functionality of "natural" DNA under different environmental conditions and are slowly dissecting possible scenarios that describe their evolution from simpler organic materials to living chemistry.
But Really Getting To understand how a genetic system might evolve, we need to test the limitations of the underlying chemistry.
The Hachimoji DNA allows this to happen. The new codes, labeled P, B, Z and S, are based on the same type of nitrogen-containing molecules as those present as purines and pyrimidines.
Similarly, they combine with hydrogen bonds to form their own base pairs – S bonding with B and P with Z.
Here the similarities fade. These new "letters" introduce dozens of new chemical parameters into the double helix structure that potentially affect how they are zipped and twisted.
By designing models that predict the stability of the molecule and studying the actual structures of this "foreign" DNA, the researchers are better equipped, which is really important when it comes to the basics of a genetic template.
Researchers constructed hundreds of Hachimoji helices built from various configurations of natural and synthetic bases, then subjected them to a series of conditions to see how well they behave.
While there were some small differences in the way New Letters did not behave, there was no reason to believe that hachimoji DNA could not work well, because an information-bearing template could mutate and evolve.
The team not only showed that their synthetic letters can contribute to new codes without quickly disintegrating sequences were also translated into synthetic RNA versions.
Her work lags far behind a second genesis. However, a novel DNA format like this one step is one way of determining what living chemistry might look like anywhere else in the universe – and not at all.
"Life-tracking is an increasingly important goal for NASA planetary missionary missionaries, and this new work will help us develop effective tools and experiments that will expand the scope of what we seek," says Lori Glaze. the Acting Director of the NASA Planetary Science Division.
Developing new foundations that can work alongside our own DNA also has applications that are approaching home, not just as a way to re-code life with a different codebase, but in our effort to build new types of nanostructures.
Heaven is not the limit with synthetic DNA. This leads us to the stars and back again.
This research was published in Science .