Scientists Discover Synthetic Cell with Reduced Genome Can Evolve as Quickly as a Normal Cell
Evolutionary biologist Jay T. Lennon and his team have made a groundbreaking discovery in their study of a synthetic minimal cell. By eliminating 45% of its genes, the researchers were able to reduce the cell to the smallest set of genes required for autonomous life. Despite its stripped-down genome, Lennon’s team found that this minimal cell evolved just as quickly as a regular cell, highlighting the resilience of life.
The research, conducted at Indiana University Bloomington, focused on a synthetically constructed minimal cell called Mycoplasma mycoides JCVI-syn3B. This cell is a minimized version of the bacterium M. mycoides and contains only 493 essential genes—the smallest genome of any known free-living organism.
The experiment aimed to determine how the minimal cell would respond to the forces of evolution over time, given its limited genes and potential constraints on adaptation. The researchers discovered that the minimal cell had an exceptionally high mutation rate, which allowed for rapid evolution.
To test the cell’s adaptability, the team grew it in the lab for 300 days, equivalent to around 40,000 years of human evolution. They then compared the evolved minimal cells to the original non-minimal version and to a strain of minimal cells that had not undergone evolution. The evolved minimal cells outperformed the unevolved ones and regained all the fitness they had lost due to genome streamlining.
Further analysis revealed that certain genes, particularly those involved in cell surface construction, underwent significant changes during evolution. However, the functions of several other genes remain unknown.
The study, published in the journal Nature, sheds light on the capacity of organisms to adapt even with a reduced genome. It challenges the notion that organisms with streamlined genomes have fewer opportunities for positive selection and adaptation.
Understanding how organisms with simplified genomes overcome evolutionary challenges has important implications in various fields, including the treatment of clinical pathogens, the refining of engineered microorganisms, and the origin of life itself. This research demonstrates the power of natural selection in optimizing fitness in the simplest autonomous organism, showing that life indeed finds a way.