Comparing those genomes with those of people without schizophrenia has allowed investigators to discovery of many genes have a profound impact on a person’s risk of developing the disease. By being able to sequence multiple genomes faster and cheaper, Gabriel says they should be able to find additional genes that have a more subtle impact on disease conditions. “Once you have bigger data, the signal becomes clearer,” she says.
Jeremy Schmutz, an investigator at the HudsonAlpha Institute of Biotechnology, agrees with the new sequencing technology. “This reduction in sequencing costs allows you to scale and perform larger studies.” For Schmutz, who studies plants, cheaper sequencing would allow him to generate more reference genomes to better study how heredity affects physical or phenotypic traits of plants. tree. Large genomic studies could help improve agriculture by speeding up the breeding of certain desirable crops, he said.
Illumina sequencing uses a method called “sequencing by synthesis” to decode DNA. First, the process requires DNA strands, usually in the form of a double helix, to be separated into single strands. The DNA is then broken down into short fragments that are spread onto the flow cell – a glass surface the size of a smartphone. When a flow cell is loaded into the sequencer, the machine attaches color-coded fluorescent tags to each base: A, C, G, and T. For example, blue might correspond to the letter A Each DNA fragment is copied one base at a time, and a matching DNA sequence is gradually created, or synthesized. A laser scans them one by one while a camera records the color code for each letter. This process is repeated until all segments are arranged in sequence.
For its latest machines, Illumina has invented denser flow cells to increase data yield and new chemistry reagents, allowing for faster reading of bases. “The molecules in that sequenced chemistry are much stronger. They can resist heat, they can resist water, and because they’re so much harder, we can expose them to more lasers and can scan them faster. It’s the heart of the engine that allows us to get more data faster and at a lower cost,” said Alex Aravanis, Illumina’s Chief Technology Officer.
That said, while the cost per genome is going down, for now, the startup costs for a machine are high. Illumina’s new system will cost around $1 million, about the same as its existing machines. Their high price is a major reason they are not yet popular in smaller laboratories and hospitals, or in rural areas.
Another thing is that they also require experts to operate machines and process data. But Illumina sequencing is fully automated and generates a report comparing each sample to a reference genome. This automation can democratize sequencing, says Aravanis, so that facilities without large teams of scientists and engineers can operate machines with few resources. The system also stores data on an internal computer, whereas with previous models that data needed to be stored elsewhere.
