Resilience of Synthetic Minimal Cells: Evolution Occurs Even with Reduced Genomes

Scientists have made a groundbreaking discovery in the field of synthetic biology. Evolutionary biologist Jay T. Lennon and his team have been studying a synthetic minimal cell that has been stripped of 45% of its genes, leaving only the essential genes required for autonomous life. Surprisingly, the researchers found that this minimal cell evolved just as quickly as a regular cell, demonstrating the inherent resilience of life.

The study, published in the journal Nature, focused on a synthetic organism called Mycoplasma mycoides JCVI-syn3B. This organism is a minimized version of the bacterium M. mycoides, which is commonly found in the guts of goats and similar animals. Over time, the natural bacterium has lost many of its genes as it evolved to depend on its host for nutrition. In 2016, researchers at the J. Craig Venter Institute further reduced the genome of M. mycoides, eliminating 45% of its genes and creating the minimal genome of M. mycoides JCVI-syn3B.

Despite its reduced genome, the minimal cell was able to grow and divide in laboratory conditions. Lennon and his team wanted to understand how this minimal cell would respond to the forces of evolution over time. They allowed the minimal cell to evolve freely for 300 days, equivalent to 2000 bacterial generations or about 40,000 years of human evolution.

The researchers then compared the evolved minimal cells to the original non-minimal M. mycoides and a strain of minimal cells that hadn’t evolved for 300 days. They found that the non-minimal version easily outcompeted the unevolved minimal version. However, the minimal cells that had evolved for 300 days performed much better, effectively recovering all of the fitness that they had lost due to genome streamlining.

The researchers identified the genes that changed the most during evolution, with some involved in constructing the surface of the cell. However, the functions of several other genes remain unknown.

This study has important implications for understanding how organisms with simplified genomes overcome evolutionary challenges. It has potential applications in various fields, including the treatment of clinical pathogens, the persistence of host-associated endosymbionts, the refinement of engineered microorganisms, and even the origin of life itself.

Overall, this research demonstrates the power of natural selection to rapidly optimize fitness in the simplest autonomous organism, highlighting the resilience and adaptability of life. As Ian Malcolm famously said in the movie Jurassic Park, “Life finds a way.”

How does the behavior of the minimal cell compare to that of a regular cell in terms of growth rate, gene expression patterns, and genetic mutations

Ural version of M. mycoides has lost many of its genes that are no longer necessary for survival in its environment. Lennon and his team took this concept further and created a synthetic version of the cell with even fewer genes.

To achieve this, the researchers used a technique called genome minimization. They started with the complete genome of M. mycoides, which contains around 900 genes, and systematically removed non-essential genes. This resulted in the creation of a minimal cell with only 437 genes, approximately 45% fewer than the natural version.

The researchers were curious to see how this minimal cell would behave in comparison to a regular cell. They conducted experiments to measure the cell’s growth rate, gene expression patterns, and genetic mutations. Surprisingly, they found that the minimal cell exhibited similar patterns of growth and mutation as a regular cell, suggesting that it is just as adaptable and resilient.

This discovery challenges the common notion that living organisms are optimized and cannot function below a certain threshold of genetic complexity. It shows that even with a significantly reduced genome, the cell is still capable of evolving and adapting to its environment.

The implications of this research are significant for the field of synthetic biology. Genome minimization techniques could potentially be used to create cells with specific functions or characteristics. By stripping away unnecessary genes, scientists can create more streamlined and efficient organisms for biotechnological applications.

Additionally, this research provides further evidence for the robustness and evolvability of life. It demonstrates that life can adapt and survive with minimal genetic information, which has implications for our understanding of the origin and evolution of life on Earth.

Overall, this groundbreaking discovery in synthetic biology highlights the inherent resilience and adaptability of life. It opens up new possibilities for designing and engineering organisms with specific traits, and deepens our understanding of the fundamental principles of life itself.