In brief: After a scientist added X and Y nucleotide bases to E. coli bacteria's natural genetic alphabet, the DNA generated new proteins. This is the first time an organism has made proteins using anything other than the natural G, C, A, and T bases.
New, Semi-Synthetic Life
At the core of all life on Earth is the molecule deoxyribonucleic acid (DNA). From the different combinations of DNA's nucleotide bases — adenine (A), cytosine (C), guanine (G), and thymine (T) — come the various genetic expressions of a living being. But what if you could add more letters to this genetic alphabet?
Back in 2014, chemical biologist Floyd Romesberg did just that. He and his team at the Scripps Research Institute in La Jolla, California, expanded the natural genetic alphabet to include an X and a Y in a strain of E.coli bacteria. Now, they've taken that work one step further through a study recently published in the journal Nature.
In this new study, Romesberg and his colleagues demonstrate how their partially synthetic strain of E.coli can process instructions from its additional X and Y nucleotide bases to express new proteins.
Creating "Artificial Life?"
Thankfully, Romesberg and his team have no intention of using their research to provoke some kind of explosion of new, hybrid life forms. As Romesberg told Reuters, his X and Y nucleotide bases can't bond with DNA's natural bases, nor can these semi-synthetic organisms (SSOs) survive outside a laboratory setting. "They can't escape," Romesberg said. "There's no Jurassic Park scenario."
Still, as University of Waterloo associate professor Brian Ingalls told Futurism, we must be cautious when dealing with the manipulation of life.
"Based on our knowledge of how life works (at the molecular level and above), it's not worthwhile to attempt a distinction between 'natural' and 'artificial'," he said. "We can, however, distinguish 'new' from 'old,' and there we should be concerned about the potential for new organisms to disrupt existing ecosystems."
As Ingalls noted, Romesberg's study is designed in such a way as to prevent such disruption. "New organisms whose molecular mechanisms are sufficiently different from (known) biochemistry are far less likely to interact in unpredictable ways with existing organisms," he said.
So, Romesberg's semi-synthetic organisms are unlikely to disrupt existing life on Earth, but could they impact the development of organic artificial intelligence (AI), for example, robots with partially biological bodies?
"What we have now is an SSO that stores and retrieves increased information. What one does with the increased information is the question," Romesberg told Futurism. "If one can develop a genetic AI, then I guess that the SSO could be used house it. The increased information and types of possible proteins available could be useful."
Our Bodies and Our World
Beyond the visions of semi-organic robots or real-life Jurassic Parks are the many far more realistic applications for Romesberg's semi-synthetic organisms. As Ingalls noted, they could help us solve many of humanity's biggest problems in health, agriculture, manufacturing, and a variety of other arenas.
The most immediate application for Romesberg's work is the development of novel protein-based drug treatments. As he told Reuters, many of the proteins that are attractive for drug treatments are quickly flushed out the body by our kidneys. His semi-synthetic DNA could be used to create proteins bearing fat molecules that would prevent this quick removal.
Beyond our bodies, these semi-synthetic organisms could be used to improve the health of our environment.
"Our long term interest is not getting bacteria and other cells to make proteins for us, but rather to see if we can get the cells to use [the proteins] themselves to gain new functions or attributes," Romesberg told Futurism. "For example, could we give bacteria proteins that allow them to break down certain hydrocarbons that we could then use to clean up oil spills?"
Generally speaking, researchers could program these proteins to give cells some new advantages under certain conditions, said Romesberg. In this way, they could prompt evolution to find new solutions to adapt to outside circumstances.
Romesberg's team plans to continue pushing their research on semi-synthetic organisms to new levels. They hope to expand the genetic alphabet of cells from organisms more complex than E.coli, such as yeast or humans, and they're also starting to consider doing the same for an intact organism, such as C. elegans worms, he told Futurism.