Scientist Kate Adamala and colleagues at the University of Minnesota built SpudCell, a synthetic cell system made from non-living components. It can copy DNA, replicate in a primitive way, and complete a full cell cycle about five times.
That makes SpudCell the first synthetic cell system built from non-living components to finish a full cell cycle. Adamala said, "I think I would be satisfied with calling it living if it’s replicating indefinitely and if it’s capable of Darwinian evolution".
University of Minnesota SpudCell
The prototype uses 36 existing bacterial genes, engineered into seven circular pieces of DNA. Most of the genes come from E. coli, some come from phage viruses that infect bacteria, and one gene makes a fluorescent protein from jellyfish so the cells can be seen.
Adamala and colleagues started with 36 genes rather than deleting genes from an existing bacterial genome. That reversed the usual minimal-cell approach and put the system on a smaller, defined starting set from the beginning.
Seven pieces of DNA
The researchers showed that some bubbles ended up with all seven parts of the genome. Two of the genes code for proteins that form pores in the membrane, letting some small molecules enter.
Larger molecules are supplied in small bubbles that fuse with the cells, and the cell is supplied with all the building blocks of life because it cannot make any itself. The system can do some things living cells do, but it still fails after about five divisions.
Open source SpudCell
The team is making the SpudCell project open source so it can be developed further. Adamala said she would call it living only if it can replicate indefinitely and do Darwinian evolution, leaving the next step squarely on that test.
