Researchers have created the first living organism with DNA synthesized entirely from scratch, according to The New York Times. Experts say the milestone achievement has created a new form of life and proven that organisms can exist with a limited and synthetic genetic code. Such synthetic life could one day be used to create medicines and other materials, and could help scientists understand how the genetic code initially formed in the development of life on Earth.
University of Cambridge researchers announced the milestone accomplishment on Wednesday in the journal Nature. They created a synthetic version of an E. Coli microbe, bacteria that is found in soil and the human gut microbiome. To do so, the researchers synthesized a genome that was four times as large, and more complex than, any previous effort.
The genome is four million base pairs long, and required the use of entirely new methods.
“It was completely unclear whether it was possible to make a genome this large and whether it was possible to change it so much,” according to Jason Chin, the molecular biologist who led the research.
Chin set out to understand the way genetic information is encoded in life. DNA inside a cell contains the instructions it needs to grow and function. DNA is composed of trios of bases in the strand called codons, which direct the production of amino acids in the cell. But despite the fact that there are only 20 natural amino acids, they are encoded by 61 different codons rather than 20 (as well as three additional codons that tell DNA when to stop amino acid construction, like the period in a sentence).
Scientists do not understand why the genetic code contains these redundancies. And it was unclear whether these extra pieces of DNA were essential to life.
“Because life universally uses 64 codons, we really didn’t have an answer,” Chin said.
The researchers removed the redundant codons from the E. Coli DNA, replacing the code of the microbe with chemically synthesized version that contained 18,000 of these edits. The result is a microbe called Syn61, and while its growth is slower and its shape unusual, it has survived.
E. Coli Is already used to create insulin for diabetes and drugs for diseases ranging from cancer to heart disease and multiple sclerosis. But the microbes are vulnerable to viruses, and this contamination can ruin an entire production run. With alternate, synthesized DNA, lab-made microbes could perhaps be designed to be immune.
Cells could also be engineered so that genes can’t escape to other species, and the process could allow scientists to design molecules with new types of chemistry.
According to Tom Ellis, an Imperial College London synthetic biology researcher who was not involved in the study:
“They have taken the field of synthetic genomics to a new level, not only successfully building the largest ever synthetic genome to date, but also making the most coding changes to a genome so far.”
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