Scientists genetically engineer artificial bacterium completely incompatible with Earth's biosphere.

https://www.dailykos.com/stories/2022/11/5/2133633/-An-entire-genome-is-made-from-scratch-to-support-a-new-genetic-code-the-result-is-a-living-organism

All lifeforms on planet Earth share the same genetic building blocks. Whether it be vertebrates, insects, mollusks, horse-shoe crabs, starfish, sponges, plants, mushrooms, eukaryota, viruses ...

Every single lifeform on planet Earth is based on a genetic code consisting of the genetic bits A, C, G, T.

Three of these genetic bits encode a byte of genetic information ("codon" ). For example, the codons TCA, TCC, TCG, TCT, AGT, AGC each refer to the amino-acid serine. Where do they refer to serine?
Proteins are synthesized by a mechanism where various forms of RNA (mRNA, tRNA and rRNA) bring the correct sequence of amino-acids together so they combine into the desired protein.





A research-group from the University of Cambridge has genetically engineered a bacterium of the strain E. coli so that their tRNA DOES NOT translate genetic information into proteins the same way AS EVERY SINGLE OTHER LIFEFORMON EARTH DOES.

TCA and TCG used to mean serine. In this artificial genome they mean alanine and histidine.

Which means that the scientists also had to re-engineer the entire genetic code and search&replace every mention of TCA or TCG with one of the other codons for serine: TCC, TCT, AGT, AGC.

Oh, and they also streamlined the codons that regulate when a genetic sequence has ended. (Like the full-stop at the end of a sentence.) TAA, TAG, TGA tell when to stop. The scientists replaced all mentions of the stop-codon TAG with the stop-codon TAA.





WHAT IS THE RESULT?

This strain of E. coli lives a normal life. They only grow and reproduce half as fast as the original strain, but are otherwise healthy and normal.

The big difference is:
THIS STRAIN CANNOT EXCHANGE GENETIC INFORMATION WITH ANY OTHER LIFEFORM ON EARTH.

Whether the bacterium recieves some DNA from another bacterium via lateral gene-transfer or whether it gets infected with a virus, nothing will happen.

The DNA of the new strain cannot interpret genes from other lifeforms, and likewise the rest of Earth's biosphere cannot interpret genes from this new strain.

This bacterium is completely immune to ANY AND ALL viruses on planet Earth. Any infection by a virus won't result in the bacterium producing more viruses: It will result in the bacterium producing random protein-garbage, because it translates the DNA of the virus into totally different proteins than those needed to make more viruses.