Illumina recently launched its NovaSeq X Series, which can sequence an entire human genome for just $200 USD! The price of sequencing a human genome has dropped from around $1000 USD in 2015 to just the price of a few dozen cheeseburgers now.
But why is this significant? A typical human’s genome is around 6.3 Giga base pairs. Each base pair is one of the 4 nucleotides: A, T, C or G, paired with its complementary partner (A with T, C with G). In total, the Illumina sequencer needs to read the combination of 6.3 billion nucleotide pairs. Being able to do so with just $200 USD is astounding.
But why would someone want their genome sequenced? Together with environmental factors, our genome (the entire collection of DNA in our body), determines what proteins we make. These proteins then determine your physical characteristics like physical appearance and presence/ absence of a disease. Our genome determines our predisposition to certain diseases, response to drugs, food allergies and much more.
But how does the sequencer actually work? This September, Illumina released their newest model: NovaSeq X Series, which is 2.5x faster than all previous models and can sequence a human genome for $200. It still uses the old sequencing by synthesis (SBS) method, but has new linkers and dyes, etc.
SBS is a method that uses fluorescently-labeled dNTPs (nucleotides without a 3’OH end, which is the ‘anchor’ for DNA synthesis) to sequence tens of millions of clusters of DNA on a surface in parallel. During each sequencing cycle, a single labeled dNTP is added to the growing DNA chain. The labeled dNTP serves as a terminator for DNA synthesis, so after each nucleotide addition, the fluorescent dye is imaged to identify the base and then cleaved to allow addition of the next nucleotide. Through imaging of around 6.3 million of these fluorescent signals, we can get the information of our genome!
Sources: https://www.fiercebiotech.com/medtech/illumina-pitches-200-genomes-new-line-dna-sequencers
https://www.illumina.com/systems/sequencing-platforms/novaseq-x-plus.html
https://www.genengnews.com/topics/omics/illumina-reveals-new-high-throughput-instrument-novaseq-x/