They evolve:

https://www.quantamagazine.org/even-synthetic-life-forms-with-a-tiny-genome-can-evolve-...

"Seven years ago, researchers showed that they could strip cells down to their barest fundamentals, creating a life form with the smallest genome that still allowed it to grow and divide in the lab. But in shedding half its genetic load, that “minimal” cell also lost some of the hardiness and adaptability that natural life evolved over billions of years. That left biologists wondering whether the reduction might have been a one-way trip: In pruning the cells down to their bare essentials, had they left the cells incapable of evolving because they could not survive a change in even one more gene?

"Now we have proof that even one of the weakest, simplest self-replicating organisms on the planet can adapt. During just 300 days of evolution in the lab, the generational equivalent of 40,000 human years, measly minimal cells regained all the fitness they had sacrificed, a team at Indiana University recently reported in the journal Nature. The researchers found that the cells responded to selection pressures about as well as the tiny bacteria from which they were derived. A second research group at the University of California, San Diego came to a similar conclusion independently in work that has been accepted for publication.

“'It turns out life, even such simple wimpy life as a minimal cell, is much more robust than we thought,” said Kate Adamala, a biochemist and assistant professor at the University of Minnesota who was not involved in either study. “You can throw rocks at it, and it’s still going to survive.” Even in a genome where every single gene serves a purpose, and a change would seemingly be detrimental, evolution molds organisms adaptively.

“'It’s a stunning achievement,” said Roseanna Zia, a physicist at the University of Missouri whose research aims to build a physics-based model of a minimal cell and who was not involved in the study. The new work showed that even without any genome resources to spare, she said, the minimal cells could increase their fitness with random changes in essential genes.

***

"They calculated that the original minimal cell had lost 53% of its relative fitness along with its nonessential genes. The minimization had “made the cell sick,” Lennon said. Yet by the end of the experiments, the minimal cells had evolved all that fitness back. They could go toe-to-toe against the ancestral bacteria.

“'That blew my mind,” said Anthony Vecchiarelli, a microbiologist at the University of Michigan who was not involved in the study. “You would think that if you have only essential genes, now you’ve really limited the amount of evolution that … can go in the positive direction.”

***

"When Lennon and Moger-Reischer adjusted for the relative fitness of the organisms, they found that the minimal cells evolved 39% faster than the synthetic M. mycoides bacteria from which they were derived.

***

"The researchers found that most of the beneficial mutations favored by natural selection in their experiments were in essential genes. But one critical mutation was in a nonessential gene called ftsZ, which codes for a protein that regulates cell division. When it mutated in M. mycoides, the bacterium grew 80% larger. Curiously, the same mutation in the minimal cell didn’t increase its size. That shows how mutations can have different functions depending on the cellular context, Lennon said. (my bold)

***

"'They observed a “fear-greed trade-off,” a tendency also seen in natural bacteria to evolve mutations in genes that will help it grow rather than mutations that would produce more DNA repair proteins to correct the errors." (my bold)

Comment: pure experimentation in a Shapiro mold. My first bold notes the use of natural selection to explain the issue, when we know bacteria can edit DNA, not natural selection. The second bold shows they recognized Shapiro's work.

Puts LUCA at 4.2 billion years ago:

https://www.science.org/content/article/our-last-common-ancestor-lived-4-2-billion-year...

"The last ancestor shared by all living organisms was a microbe that lived 4.2 billion years ago, had a fairly large genome encoding some 2600 proteins, enjoyed a diet of hydrogen gas and carbon dioxide, and harbored a rudimentary immune system for fighting off viral invaders. That’s the conclusion of a new study that compared the genomes of a diverse range of 700 modern microbes and looked for commonalities to identify which features arose first. Although the analysis doesn’t reveal how life got its start, it suggests a complex cellular organism somewhat similar to modern microbes evolved only a few hundred million years after Earth’s formation.

***

"Moody and his colleagues have gone a step further. They focused on five sets of “paralog,” or duplicated, genes that were found in multiple bacteria and archaea, suggesting the doubling happened prior to LUCA’s split into those descendants. Tracking whether a mutation is in both copies of those genes or just one makes it easier to pin down the timing of their duplication and thus the ages of common ancestors, Moody says.

"In so doing, their analysis suggested LUCA lived some 4.2 billion years ago. “It’s maybe a little bit earlier than other estimates, but not much,” says Rika Anderson, an evolutionary microbiologist at Carleton College who was not involved with the work.

"To probe LUCA’s lifestyle like Martin did, Moody’s group tracked 57 “marker” genes across 350 bacteria and 350 archaea species to construct a tree of life. That’s an advance over Martin’s team, which tracked genes shared by at least two orders of bacteria and two orders of archaea, Moody says. His team then separately tracked the evolutionary patterns of individual genes and gene families of all the available genes in those bacteria and archaea cataloged in a commonly used genomic database. By comparing the evolutionary histories of individual genes with those of the species, they could better determine what genes were duplicated, lost, or underwent horizontal gene transfer. From that, they deduced what was present in LUCA.

“'It’s a more robust approach,” Anderson says. But Martin counters that despite this effort “they get exactly the same result, 8 years later.”

"Indeed, the U.K. team’s analysis suggested LUCA fueled itself on a diet of carbon dioxide (CO2) and H2, as Martin has found. But they also found evidence LUCA had a gene that could have protected it from ultraviolet light, which suggests the microbe might have lived in surface waters, where it could have captured CO2 and H2 from the atmosphere, rather than at deep-sea vents. Still, like Martin, they spotted the signature of an enzyme called reverse gyrase that is commonly found in thermophiles, which they acknowledge means LUCA could also have thrived around those vents.

"Moody also found something new: that LUCA likely had 19 CRISPR-Cas9 genes, an apparatus modern bacteria rely on to chop up the genetic material of viral invaders (and the inspiration for the versatile genome editor now used in many fields). “LUCA had this early immune system as a way of avoiding viruses,” Moody says.

"That thrills Kaçar, as it hints at a thriving ecosystem of microbes and pathogens that far back. Anderson is equally enthused, noting that CRISPR-Cas9 systems are “kind of sophisticated.” That means in only a few hundred million years, early life managed to evolve complex microbes whose interactions quickly settled into the scaffolding of a simple ecosystem—a feat that modern studies trying to depict the long-lost LUCA can’t yet explain."

Comment: only 300.000 years after Earth formation, and complex life appeared. Much too quick for random mutations doing the job. More evidence for design.