Stephen Benner etal strike again!:

Hachimoji DNA doubles the genetic code:
Researchers in the US have built an “alien” DNA system from eight building block letters, so expanding the genetic code from four and doubling its information density. The new system meets all of the requirements for Darwinian evolution and can also be transcribed to RNA. It will be important for future synthetic biology applications and expands the scope of molecular structures that might be capable of supporting life, both here on Earth and more widely in the universe.
However:
It is wrong to say that hachimoji DNA is alien life though, he <Benner> insists. For that, the system must also be self-sustaining and hachimoji DNA needs a steady supply of the lab-created building blocks and proteins. “As none of these are available outside, hachimoji DNA can go nowhere if it escapes the laboratory.”
.. Close .. (but no cigar)!