Indiana University School of Medicine
It's been more than 65 years since James Watson and Francis Crick collaborated With Rosalind Franklin and Maurice Wilkins discovered that DNA ̵
Since then, astrobiologists have attempted to conjure up the countless shapes and forms in which life is found on other planets. And an important part of this imagination requires the determination of the permutations and combinations in which DNA could be assembled in such extraterrestrial organisms, as opposed to those found in living beings on Earth .
In a monumental achievement on this journey, scientists funded by NASA and directed by the Foundation for Applied Molecular Evolution in the US have synthesized a new stable version of DNA with eight base molecules compared to the Form that four were found on earth.
Traditionally, the stable molecular structure of DNA is maintained by the chemical bonding between its base molecules. Adenine, guanine, thymine and cytosine. And between these bases, represented by the letters A, G, T, and C, respectively, a chemical bond occurs only between A and T and G and C, leading to the complex double-helix structure of DNA.
Scientists have discovered over the years that these bases can form double-helical structures in one of the three forms – A, B or Z . While the B-form is most common, occasionally A and Z types were also found, with the Z-form helices being left-handed.
Even with these forms, the bases and their mating configuration remained the same. The exclusivity of this binding plays an important role in the stability of the DNA molecule and is therefore one of the main reasons why today all life forms on Earth exist. According to project leader Steven Benner however, the building block of our genetic code could have had more forms.
The bases not only play a structural role but also encode information about what molecules an organism can produce in its body. In each cell, there are mechanisms to read the DNA bases and, correspondingly, to produce molecules that are assembled into different structures. It's like workers in a factory reading the source file for a car's design – which resembles DNA – to put together the different parts of a car.
The version synthesized by Benner's team is called Hachimoji DNA . 19659014]; Hachi means eight in Japan and moji translates to "letter". The synthetic DNA has the four traditional bases and four unnatural bases, including a pair named S and B. This means that it is possible to encode more defined information with the eight bases than has traditionally been possible only with A, T, G and C is possible.
This study is remarkable for me because it has proven that there is nothing special about the DNA found on Earth, and that there could be other stable forms in the universe that have other combinations of other molecules. Benner's creation also raises the question of whether life here on Earth could have taken a different path with an eight-base DNA.
This article examines how the study was conducted. If you want to examine the properties of the newly synthesized bases, Zimmer's contribution is worth reading.
TNW Conference 2019 is coming! Click here to see our glorious new location, the inspiring range of speakers and activities, and part of this annual tech bonanza.