PacBio Releases New Chemistry
By Bio-IT World Staff
October 16, 2014 | Pacific Biosciences, maker of the RSII sequencing instrument, has launched a new reagent kit to increase both the throughput and read length of its sequencers. The update to PacBio's chemistry comes ahead of a suggested release date in early 2015. The new kit, P6-C4, uses a new polymerase and new chemistry, replacing the current P5-C3 kit. All PacBio polymerases are derived from a naturally-occurring enzyme found in the φ29 bacteriophage, which forms the basis of a technology that reads DNA and RNA in fragments over an order of magnitude longer than any other system now on the market.
PacBio reports that the P6-C4 chemistry delivers average read lengths of over 10,000 bases, with an N50 of more than 14 kb — meaning half of all sequence data occurs in reads longer than 14,000 bases. The previous P5-C3 chemistry had delivered an N50 of around 10 kb bases for most users. P6-C4 will also reportedly boost the throughput of RSII sequencers, to between 500 million and 1 billion bases per cell, according to PacBio.
While Pacific Biosciences was founded with ambitions to become a leading player in routine sequencing, lately the company has made a full court press on niche applications opened up by its long reads. These include transcriptome sequencing to identify alternate splicing of RNA molecules, better resolution of highly repetitive regions of the genome, and the ability to more easily assemble whole genomes from scratch, rather than mapping reads to a preexisting reference genome. (For some interesting use cases, see "PacBio Users Share New Tools and Applications at Meeting in Baltimore.")
As a demonstration of the new chemistry, PacBio has also publicly released a complete data set for the model organism Caenorhabditis elegans through Amazon Web Services. The C. elegans genome was sequenced with an N50 of over 21,000 bases, and one read consisting of 64,500 bases. As recently as a year ago, the longest read the company had ever recorded was just over 40,000 bases long.