Can evolution represent its magic on a miniature canvas? A study involving a synthetic lifeform with the simplest attainable genome yielded an affirmative answer. Proving that irrespective of an organism’s complexity, survival instinct continues to ring true, and evolution relentlessly refines its form.
Scientists at Indiana University Bloomington posed an intriguing proposition. What if a life form possesses only quintessential genes? Does it offer sufficient scope for evolution? Or does the risk of minor changes posing an existential threat outweigh the potential for evolution?
Guided by this question, they experimented with a novel creature of synthetic life modeled after the natural organism, Mycoplasma mycoides, known for its minimalistic genome of 901 genes. In 2016, this was trimmed down to basic necessities, a mere 500 genes compared to E. coli’s extensive genome comprising over 4000 genes. In a follow-up study, some genes were reintroduced, helping synthetic cells multiply and mobilize. For the recent study, researchers focused on an iteration known as JCVI-syn3B, with merely 493 genes.
“Every single gene in its genome is essential,” says Lennon about the M. mycoides JCVI-syn3B. “One could hypothesize that there is no wiggle room for mutations, which could constrain its potential to evolve.”
The scientists subjected this strain to lab conditions for 300 days, witnessing the evolution of 2000 generations within this version of synthetic life, roughly the equivalent of 40,000 years in human terms.
Research lead Jay Lennon observes that every gene carried by this strain is essential, which theoretically, could limit mutation scope and hamper its evolutionary potential. After the 300-day term, the strain was moved to a competitive arena to challenge a strain of the synthetic organism that hadn’t undergone evolution and the natural M. mycoides bacterium.
Predictably, the naturally evolved bacterium, courtesy of its richer genome, emerged victorious. However, the post-evolution strain of JCVI-syn3B displayed astounding adaptability, retrieving almost all the lost fitness initially stripped from its genome. On examining further, researchers found significant evolution occurred in genes responsible for creating the cell’s outer surface.
This ground-breaking research amplifies our understanding of life’s adaptability, enlightening the path for probable applications in pathogen treatment, bio-engineering of microbes for specified tasks, and the journey to uncover life’s origins.
Lennon concluded, “Life exhibits astounding robustness. You can simplify it down to the barest essentials, and yet evolution won’t be deterred from optimizing it.” This pioneering research has been published in Nature.
