Image : NASA / JPL-Caltech / Space Science Institute  According to a recent article, there could be a million different structures that can store genetic information.
DNA stores the genetic information that describes the entire life of the Earth in the form of a twisted framework that is lined with a sequence of a series of elements of four data-encoding molecules. But is DNA the best way to store biological data for any purpose? What if there were better molecules for other purposes?
The new research suggests that "large spaces of unexplored chemistry for pharmacology and biochemistry exist and efforts are made to understand the origins of life," according to the publication published in the Journal of Chemical Information and Modeling.
The researchers discovered the multitude of potential data storage molecules with a program called MOLGEN 5.0. They first determined what a nucleic acid-like component should be made of starting with a "fuzzy" base molecular formula. They also defined what its structure should look like: it needs a part that can recognize another molecule that reads the component as data (in DNA this is the A, T, C and G or nucleobase) as well as points to connect the recognizable entity with the scaffold and connect each of these components to form a larger molecule. Then they used another program called Pipeline Pilot to create new structures with the same chemical formulas to see what they might have missed. Finally, they compared the output to databases of molecules to determine if any of their new molecules already existed, and used a different computer program to exclude molecules that violated various chemical restrictions.
Nobody actually produced these molecules. According to the paper, this work is "the first systematic attempt" to list, count and describe the space of all nucleic acid-like molecules.
Initially, this team of scientists simply studied molecules with the same chemical formula but with a different structure than RNA – the single-stranded copies of DNA that the body actually uses as instructions to build proteins. Extending this study to more general chemical formulas revealed an enormous list of unexplained possibilities of what genetic material might look like: 1,160,990 different structures.
"It's really exciting to consider the potential of alternative genetic systems based on these analogous nucleosides – they may have originated and evolved in different environments, perhaps even on other planets or moons in our solar system," study author Jay Goodwin said. Senior Research Fellow in Chemistry at Emory University said in a press release. "These alternative genetic systems could extend our concept of 'central dogma' of biology into new evolutionary directions, in response [to] and robust to increasingly challenging environments here on Earth"
Source of RNA and DNA and why they look like Earth. It could also help synthetic biologists to use DNA-like molecules as biological stores .
It's exciting stuff. "This paper is a remarkably thorough analysis," said George Church, a professor of genetics at Harvard Medical School, Gizmodo in an e-mail. Now that such an analysis is in place, "we might wonder how quickly the community is creating it and checking its usefulness."
In other words, now that the list is out there, scientists have to start looking around and find out if any of these potential molecules can be used in the real world.