Us scientists up to date the simplest life form the simplest form of life scientists made so far
US scientists have stripped life back to its bare essentials — creating a synthetic microbe with the absolute minimum genetic information needed to grow and reproduce.
The researchers, led by Craig Venter, the genomics pioneer, made Syn3.0, the “minimal synthetic bacterial cell”, as a follow-up to their much publicised creation in 2010 of Syn1.0, the first living cell with DNA (its genome) made from scratch using laboratory chemicals.
They hope Syn3.0 or its successors will provide a platform to which synthetic biologists can add genes for particular purposes, such as producing drugs or biofuels, though the more immediate aim is to understand better the fundamental biochemistry of life.
The project, published in the journal Science, took four years longer than expected, Dr Venter said, and revealed “surprising” gaps in biological knowledge.
The initial approach was to design a minimal bacterial genome using all the information available from the scientific literature, but that failed. The failure shows that “our current knowledge of biology is not sufficient to sit down and design a living organism and build it”, he said.
Instead, the team went back to Syn3.0, which was based on Mycoplasma mycoides, the naturally occurring bacterium, and began the long process of discovering which of its 901 genes were essential for life by finding out what happened when each one was deleted.
One by one the unnecessary genes were eliminated until the team, working in California at the J Craig Venter Institute and Synthetic Genomics, its associated company, was left with 473 genes essential for replication and growth.
The DNA encoding these 473 genes, amounting to 531,000 chemical “letters” of genetic code, was then synthesised in the lab and the resulting synthetic genome transplanted into the shell of M capriolum, another bacterium whose own DNA had been removed.
The synthetic genome took over the biological machinery of the host cell, producing a healthy bacterium that reproduces rapidly in lab cultures and doubles its colony size every three hours.