Researchers pioneer DNA synthesis method that creates genes faster, cheaper

Berkeley Lab/Courtesy

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Researchers from the Joint BioEnergy Institute, a scientific partnership led by the Lawrence Berkeley National Laboratory, have pioneered a cheaper and safer way to synthesize DNA, with less waste than current methods.

This technology uses enzymes, or substances that speed up biological reactions, to synthesize new DNA. Researchers hope to utilize this new technology to engineer microbes to produce medicines, fuels and more — all biologically.

“We can engineer microbes to produce our fuel, our plastics, our medicines,” said Tristan de Rond, a campus researcher on the project who recently finished his doctorate in chemistry.

Many aspects of biological research and bioengineering require DNA synthesis. Creating synthetic DNA is a way to “redesign biology to suit contemporary human needs,” said Justine Kang, another researcher on the project and a campus senior, in an email.

Currently, ordering a gene costs upwards of a hundred dollars and takes at least two weeks, according to the study’s lead co-author and visiting doctoral student Sebastian Palluk. This new technique is still in its preliminary stages, and Kang said in an email that it is expected to become much faster, allowing biologists to order, or even print their own, DNA in less time.

“Imagine when you’re making a computer, if you still had to solder your own parts,” de Rond said. “In biology, we spend a lot of time constructing the parts we want to use, instead of using those parts.”

This new technique uses an enzyme called a template-independent polymerase terminal deoxynucleotidyl transferase, or TdT, where nucleotides are added one by one, creating a brand new strand from scratch. The enzyme normally adds many of the same base pair — A, G, C or T — to a strand, but has been engineered to add only one and then stop, washing the enzyme away before adding a new one.

“Enzymes are extremely specific, so that we expect that no undesired side-reactions occur,” Palluk said in an email. “In addition, TdT, the enzyme we use, is very fast –  it can add up to 200 bases a minute if you let it free wheel.”

Older methods of DNA synthesis are based in organic chemistry. They required an incredibly sterile environment with no water, and produced waste hazardous to both the environment and human health. After decades of refinement, this method can only synthesize around 200 base pairs at a time — the average gene is thousands of base pairs long.

This new technique occurs in water using biological agents, making it cheaper and easier to use than the previous method that employed only chemical reagents. This could make it easier to use in places where sterilization is difficult and in space, where chemical solvents are less readily available.

“What sets our work apart, though, is that our biology can be improved upon,” Kang said in an email. “It raises the ceiling on what’s possible — accuracy, speed, environmental impact — you name it.”

Contact Madeleine Gregory at [email protected] and follow her on Twitter at @mgregory_dc.