Minimalist cell whittled down to 473 genes
A type of bacteria with nearly 1,000 genes can live and replicate with less than half – and the exact job of a third of those remaining genes has researchers stumped. Amy Middleton reports.
The simplest replicating cell, stripped back to include only the genes absolutely necessary to live, has been created by a team of researchers two decades after they made it their mission.
The minimal Mycoplasma mycoides bacterial cell, which contains just 473 genes, was designed to help scientists figure out the purpose and function of every essential gene in a living cell.
The research team, headed by American geneticists Craig Venter and Clyde Hutchison, is renowned for another revolutionary accomplishment: in 2010, they succeeded in activating the first synthetic, self-replicating bacterial cell, designed by a computer and built in a lab.
Initially, the team designed eight hypothetical minimal cells, and rigorously tested each to see which genes were essential to life, and which weren’t.
As the researchers built their prototype, they used foreign sequences of DNA to disrupt the activity of each gene, in turn figuring out which were necessary to keep the cell alive and functioning.
Those deemed non-essential were chopped out, such as genes that are required for growth, but not necessarily required for the simplest form of life.
Once the minimal cell had been whittled down to its simplest form, they analysed its makeup. Of the 473 genes identified by the team as “essential to life”, the exact role of 31% of those genes remains a mystery.
Although some genes within the cell do perform essential functions, their role may have been duplicated by another gene, so they were removed.
The end product, given the catchy title JCVI-syn3.0, is smaller than any naturally occurring, self-replicating cell known to science.
JCVI-syn3.0 was published in Science.