Five years ago, scientists created a single-celled synthetic organism that, with only 473 genes, was the simplest living cell ever known. However, this bacteria-like organism behaved strangely when growing and dividing, producing cells with wildly different shapes and sizes. Now, scientists have identified seven genes that can be added to tame the cells' unruly nature, causing them to neatly divide into uniform orbs. The National Institute of Standards and Technology (NIST) reports: Scientists at JCVI constructed the first cell with a synthetic genome in 2010. They didn't build that cell completely from scratch. Instead, they started with cells from a very simple type of bacteria called a mycoplasma. They destroyed the DNA in those cells and replaced it with DNA that was designed on a computer and synthesized in a lab. This was the first organism in the history of life on Earth to have an entirely synthetic genome. They called it JCVI-syn1.0.
Since then, scientists have been working to strip that organism down to its minimum genetic components. The super-simple cell they created five years ago, dubbed JCVI-syn3.0, was perhaps too minimalist. The researchers have now added 19 genes back to this cell, including the seven needed for normal cell division, to create the new variant, JCVI-syn3A. This variant has fewer than 500 genes. To put that number in perspective, the E. coli bacteria that live in your gut have about 4,000 genes. A human cell has around 30,000.
NIST's role was to measure the resulting changes under a microscope. [...] The result was stop-motion video that showed the synthetic cells growing and dividing. This video shows JCVI-syn3.0 cells -- the ones created five years ago -- dividing into different shapes and sizes. Some of the cells form filaments. Others appear to not fully separate and line up like beads on a string. Despite the variety, all these cells are genetically identical. These videos and others like them allowed the researchers to observe how their genetic manipulations affected the cell growth and division. If removing a gene disrupted the normal process, they'd put it back and try another. Of the seven genes added to this organism for normal cell division, scientists know what only two of them do. The findings have been published in the journal Cell.
