Summary of Key Points
A team of synthetic biologists from the University of Minnesota in the United States has created a synthetic cell called “SpudCell.” This cell is assembled from non-living materials and can replicate DNA and divide, much like a living cell. However, it is not yet considered a true living cell because it relies heavily on external supplies of raw materials and loses its functionality after about five divisions. The significance of this achievement lies in the fact that SpudCell was constructed using a “bottom-up” approach, as opposed to previous methods that involved deleting genes from existing bacteria. The team has made the project open-source, hoping that scientists around the world can contribute to its improvement with the goal of creating the simplest form of artificial life that can divide indefinitely.
Detailed Explanation
1. What makes SpudCell different from previous synthetic cells?
Previous synthetic cells were created by “subtracting” genes from existing bacteria; for example, in 2016, scientists reduced the number of genes in a bacterium from 901 to 473. In contrast, SpudCell was created by “adding” genes—specifically, 36 genes from E. coli, phage viruses, and jellyfish (which provide fluorescent protein genes for observation). Essentially, SpudCell is built from scratch, rather than modifying existing organisms.
2. Is SpudCell considered a living cell?
Strictly speaking, no. Although it can perform two key functions of living cells (replicating DNA and dividing), it has two major limitations:
- Dependence on external supplies: SpudCell cannot synthesize its own materials (such as proteins or small molecules) and relies entirely on the laboratory for these resources.
- Lack of natural evolution: It can only be modified with beneficial mutations introduced by humans; it does not undergo random mutation and natural selection like living cells.
The team leader, Adamares, stated, “It will only be considered a true living cell when it can replicate indefinitely and mutate and evolve on its own.”
3. How was SpudCell created?
The process involved the following steps:
1. The 36 genes were organized into seven circular strands of DNA, which were then replicated in large quantities.
2. These DNA strands were placed in a solution containing lipids and other materials; the lipids spontaneously formed vesicles that encapsulated all seven DNA strands, resulting in SpudCell.
4. How does SpudCell divide?
When larger protein molecules are added to the solution, they compete with the channel proteins on the cell membrane of SpudCell for space, causing the membrane to bend and form buds. These buds break off to become new cells. However, since the new cells randomly inherit parts of the DNA, many do not contain all 36 genes, limiting their lifespan.
5. Current challenges and future goals
- Current challenge: SpudCell loses its function after five divisions because it cannot synthesize ribosomes (the cellular “protein factories”) on its own and relies on externally provided ribosomes.
- Future goals:
- Integrating all 36 genes into a single DNA strand to reduce the risk of gene deficiency in new cells.
- Enabling SpudCell to synthesize its own ribosomes, which Adamares believes could be achieved in the near future, allowing for unlimited division.
6. Is SpudCell safe?
There is no risk associated with SpudCell. Even if it becomes capable of surviving on its own, it would only be able to do so in a controlled laboratory environment where all necessary materials are available. It would be even safer than common bacteria, as it cannot spread outside such environments.
While SpudCell is not yet a true living cell, this breakthrough opens new possibilities for synthetic biology. It could potentially be used in drug production, environmental cleanup, and the study of the origins of life. However, much more research and optimization are needed before these applications become feasible.