Comparing these genomes to those of people without schizophrenia allowed researchers to discover multiple genes that have profound effects on a person’s risk of developing schizophrenia. By being able to sequence more genomes faster and cheaper, they will be able to find other genes that have more subtle effects on the condition, Gabriel said. “Once you have bigger data, the signal becomes clearer,” she said.
“This kind of thing shakes up everything you’re working on,” agrees Jeremy Schmutz, a researcher at the HudsonAlpha Institute for Biotechnology, of the new sequencing technology. “The lower cost of sequencing allows you to scale up and do more large studies.” For Schmutz, who studies plants, cheaper sequencing will allow him to generate more reference genomes to better study genetics How to affect a plant’s physical characteristics or phenotype. He said large genome studies could help improve agriculture by accelerating the breeding of certain desirable crops.
Illumina’s sequencers use a method called “sequencing by synthesis” to decipher DNA. This process first requires breaking the DNA strand, usually in the form of a double helix, into single strands. The DNA is then broken down into short fragments, which are spread over a flow cell—a glass surface the size of a smartphone. When the flow cell is loaded into the sequencer, the machine attaches color-coded fluorescent labels to each base: A, C, G, and T. For example, blue might correspond to the letter A. Each DNA segment is copied base by base, and a matching DNA strand is then gradually made or synthesized. A laser scans the bases one by one, while a camera records the color-coding of each letter. Repeat this process until every fragment has been sequenced.
For its newest machines, Illumina has invented denser flow cells to increase data throughput and new chemistries that enable faster base calls. “The molecules in this sequencing chemistry are much stronger. They are heat resistant, they are waterproof, and because they are stronger, we can make them take more laser power and scan them faster. That’s the heart of the engine. , it allows us to acquire more data faster and at a lower cost,” said Alex Aravanis, CTO of Illumina.
That said, while the cost per genome is falling, for now, the machines themselves are expensive to start. Illumina’s new system will cost about $1 million, roughly the same as the current machine. The high price is a key reason why they are not yet common in smaller laboratories and hospitals or in rural areas.
Another is that they also need experts to run the machines and process the data. But Illumina’s sequencers are fully automated and generate a report comparing each sample to a reference genome. Such automation could democratize sequencing, Aravanis said, so facilities without large teams of scientists and engineers can run machines with few resources. The system also stores data on an internal computer, which for earlier models needed to be stored elsewhere.
