DNA and its cousin RNA store genetic information and enable life as we know it – but what if millions of lesser-known chemicals could do exactly the same?
A recent study suggests that more than 1 million chemical doppelgangers could encode biological information in the same way as DNA. The new study, published in the Journal of Chemical Information and Modeling on September 9, may point the way to new drug targets, explaining how life first developed on Earth and even we are looking for ways of life beyond our planet, wrote the authors.
"It is really exciting to consider the potential for alternative genetic systems that could have originated and evolved in different environments, perhaps even on other planets or moons in our solar system. " Co-author Jay Goodwin, a chemist at Emory University, said in a statement .
Both DNA and RNA, the two known types of nucleic acids, contain chemical components, called nucleotides, which combine in a specific order and, depending on their sequence, pass on different data, much like single letters in a written sentence. Some natural and artificial molecules mimic the basic structure of DNA, but so far no one has tried to figure out how many of these duplicates might exist, the authors wrote.
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"There are two types of nucleic acids in biology," co-author Jim Cleaves, a chemist from Tokyo Institute of Technology said in the statement. "We wanted to know if there was one or even a million more."
"The answer is that there seems to be a lot more than expected," said Cleaves.
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The authors designed a computer program to generate chemical formulas for nucleic acid-like molecules. In DNA, nucleotides combine in different pairs to form a line, so scientists can make sure that their molecules are formed in the same way. In the end, the program assembled more than 1
"We were surprised by the result of this calculation," said co-author Markus Meringer, chemist at the German Aerospace Center in Cologne, in the statement. "It would be very difficult to a priori estimate that there are more than a million nucleic acid-like scaffolds, so now we know and we can start testing some of them in the lab."
Similarly, history could clarify how life originated on Earth before DNA and RNA dominated the world of biology. Theoretically, evolution could have performed "test runs" with some of these other molecules before settling on nucleic acids as the best means of transport for genetic data, the authors suggested.
The doppelgangers could also fuel future medical advances they added. Nucleotide-like drugs are said to be used to undermine dangerous viruses and malignant cancer cells in the human body. With a library of structurally similar molecules, drug developers might be able to use DNA duplication as a major weapon in the fight against disease.
"It's absolutely fascinating to believe that we could find new drugs in our search for alternative molecules to DNA and RNA that can store genetic information using modern computing techniques," said co-author Pieter Burger, a biochemist Emory University.
Originally published on Live Science .