First, scientists have been working for decades to simplify existing life, trying to arrive at a minimal viable life form by jettisoning anything that is not essential from the simplest extant cells. The success of Craig Venter’s group is well known. Building on their efforts to produce synthetic life (“Synthia” or “Mycoplasma labritorium”) in 2010,1,2 in 2016 they introduced the current record holder for the simplest autonomously reproducing cell (JVCI Syn3.0).3 With a genome of only 473 genes and 520,000 base pairs of DNA, JVCI Syn3.0 can reproduce autonomously, but it certainly isn’t robust. Keeping it alive requires a coddling environment — essentially a life-support system. To arrive at a slightly more stable and robust organism that reproduced faster, the team later added back 19 genes to arrive at JVCI Syn3A.4 When combined, this work provides an approximate boundary for the simplest possible self-replicating life. We are clearly approaching the limit of viable cell simplicity. It seems safe to conclude that at least 400 genes (and approximately 500,000 base pairs of DNA) are the minimum requirements to produce a self-replicating cell.
(April 6, 2022)Rob Stadler, “[article title]” at Evolution News and Science Today
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The critical question is viability. Anything can be a lot simpler, at least in principle, if it does not also need to be alive.