Minimal Cell Reveals How Little We Know About Fundamental Genetics

JCVI-Syn3.0 cells magnified about 15,000 times. (Credit: Tom Deerinck and Mark Ellisman of the National Center for Imaging and Microscopy Research at the University of California at San Diego) A team of biologists has synthesized the smallest genome that can encode for a living, replicating cell, but the discovery reveals how much we still don’t know about the fundamental building blocks of life. Geneticist J. Craig Venter and his colleagues at the Venter Institute started with the genome of Mycoplasma mycoides, which is a species of bacteria with the smallest genome of any self-replicating cell scientists know of so far. They inserted a foreign genetic sequence called a transposon into one gene at a time, which stopped the gene from working so the researchers could watch what happened. If the cell kept going without the disrupted gene, the researchers labelled it as non-essential and cut it out of the genome. After four years of working their way through M. mycoides’ genome, the researchers had whittled it down to the bare minimum: 473 genes, about half of the original bacterial genome. They call the result JCVI-Syn3.0, and they published their results Thursday in the journal Science.