Going Xeno: Creating New Life to Safeguard the Old
Xenophobia is prevalent in the world at large. Human beings seem to have an inherent dislike of diversity and mixing ingrained in us, unless we somehow educate ourselves out of it. We have been like this throughout history and this is most likely why only the sapiens species have survived. Perhaps we can blame this entirely on “Nature”. Nature is xenophobic. If it wasn’t, maybe the entire living world would have had more than just one single genetic coding molecule? But DNA is alone; it did not mix, it did not mingle… for about 4 Billion years. Synthetic biologists are using this to our advantage and creating new life in the bargain.
While the fields of synthetic biology and genetic engineering are progressing rapidly, the major constraint preventing widespread application of these biological technologies is the biosafety issue. Everyone is concerned that without a foolproof plan, our engineering of biology could create massive changes to the genetic makeup of the natural world. Standard genetic engineering has certain protocols in place to avoid these concerns from manifesting in reality but synthetic biologists had to go the extra mile to prevent another misguided “GMO activism” catastrophe.
In order to have no chance whatsoever of affecting “natural” genetics with specifically engineered organisms, a few techniques emerged and evolved. At first, basic “Addiction” was employed: engineering organisms that were unable to produce certain essential metabolites on their own and unable to survive unless supplied these externally. This strategy evolved quickly to develop organisms that depended on “unnatural” compounds that would not be readily found in most natural environments. To keep up with this strategy, newer synthetic compounds were employed until we reached the point of synthetic amino acids.
Since there are three stop codons, it became possible to make one of them (amber codon) represent synthetic peptides that don’t occur in natural organisms but could be required by the engineered ones. Even if a piece of DNA like this were then to make its way into a natural life form, the DNA reading machinery would never read the stop sequence as anything but a stop sequence. Although these methods mitigate risk considerably (more than required by current policies), synthetic biologists could not stop there. The next obvious step was to create a new code for life itself.
DNA works well, ask any organism in existence today. With a few minor tweaks to its chemistry, we have achieved the creation of molecules that could work as well, but could not mix with the DNA even if it wanted to. Xeno nucleic acids (XNAs) have been developed to give synthetic biologists the freedom to create entirely separate life forms, borrowing from the abilities of current life. Trusting DNA to maintain its “you can’t sit with us” attitude will allow for existence of this new life to be our own tool that simply cannot mingle with the “natural order” that humanity is trying to preserve. This approach is being coined “genetic firewall” and some scientists consider it the ultimate biosafety tool.
Still, creating not just one, but multiple parallel forms of life could have its own long-term risks like those being foreseen in the case of AI. Combining xenobiology with other forms of biosafety such as kill switches, that turn “on” in the absence of a specifically supplied substrate will keep the escape frequencies low enough to consider escape an improbability. The last precaution would be to ensure that the synthetic DNA/XNAs are destroyed by nucleases triggered in a similar fashion to kill switches.
Building complexity into biosafety is a mandate that synthetic biologists have not only met, but surpassed by immense margins. With every new technology there must be policies and checks in place to avoid misuse and malicious applications of the technologies. Now, more than ever, scientists and policy makers are realising the need to work together so it should be safe to say that the future on synbio looks (bio)safe!