According to new research published in today’s journal Science, researchers have created a 473 gene genome which represents what they believe are genes sufficient for life and nothing else.
Why a “minimal genome?”
Researchers have created the smallest living genome know, and they hope that this dividing cell could give they and others understanding of what life truly is by reducing it to it to something that could live but not do much more. The project was envisioned by the researchers following the sequencing of the first genome completed in 1995 a simple bacterium.
“This is a study that had its origins a little over 20 years ago in 1995, when this institute sequenced the very first genome in history, Haemophilus influenzae,” said senior author J. Craig Venter, founder of the J. Craig Venter Institute, which not surprisingly focuses on genomic studies. Venter also participated that first sequenced the human genome in 2000.
“[My colleagues] and myself were discussing the philosophy of these differences in the genomes and decided the only way to answer basic questions about life would be to get to a minimal genome, and probably the only way to do that would be by trying to synthesize a genome,” Venter said in a news conference ahead of today’s publication of their paper.
“And that started our 20-year quest to do this.”
This synthetic genome is quite special as, for good or bad, nearly every living thing contains extra genes that account for growth and other necessary factors like development but aren’t necessary for simple life.
Think of it like a film editor, or even better a projectionist, splicing something together that played and nothing else.
The group’s work began with simple bacteria
The group took the genome of Mycoplasma mycoides, a parasite normally found in cows and goats and essentially used it as their canvass. The team had already built this genome from scratch six years ago before transplantation but from here they really wanted to strip it down to the essentials.
After breaking it into eight working segments, the group began paring it down with their understandings of genetics and biochemistry. The reason for splitting into eight segments was to pull out a single gene at a time and see if it was still viable.
From here they began inserting transposons (foreign genes) in order to see what they could “break” safely. From here, they removed the transposons as well as other genes deemed surplus to requirements.
Trial and error ruled the day. When the group arrived at a point where they couldn’t remove additional genes without killing the cell, essentially their work was finished.
“One of the great findings but also the great caveats of this work is that it allowed them to discover how much we don’t know, even about the core sections of the genome,” said Adam Arkin, director of the Synthetic Biology Institute at the University of California Berkeley, in a statement.
The group’s hope is that its minimalist approach will allow them and others to figure out practical applications for the genome.
“The major limitation is that this is the beginning of a very long road,” said Sriram Kosuri, an assistant professor of biochemistry at UCLA, in his statement.
“It’s not as if this new minimal genome will automatically lead to either fundamental insights or industrial applications immediately. That said, they’ve created a self-replicating biological organism that might be a better starting point for such scientific and engineering goals than continuing to study natural systems.”
