A huge question in biology is: “how many genes are necessary in order for life as we know it to exist?” Scientists have been reducing the number of genes. We had a thread about this a few years ago. Now they’ve gone further.
In 2016, researchers led by Craig Venter at the J. Craig Venter Institute in San Diego, California, announced that they had created synthetic “minimal” cells. The genome in each cell contained just 473 key genes thought to be essential for life.
The cells were named JCVI-syn3.0 after the institute and they were able to grow and divide on agar to produce clusters of cells called colonies.
But on closer inspection of the dividing cells at the time, Venter and his colleagues noticed that they weren’t splitting uniformly and evenly to produce identical daughter cells as most natural bacteria do. Instead, they were producing daughter cells of bizarre shapes and sizes.
The creators of JCVI-syn3.0 had thrown out all the parts of the genome that they thought were not essential for growth. But their definition of what was necessary for growth turned out to be what was needed to make beautiful colonies growing on an agar plate, she says, rather than what was needed to produce cells that divide in a uniform and lifelike way.
When the researchers added seven genes to JCVI-syn3.0 to produce a new synthetic cell, they found that this was enough to restore normal, uniform cell division and growth. Strychalski and her colleagues found that while two of the seven genes were already known to be involved in cell division, five were previously without a known function. It was surprising.
So, 480 key genes.