Although PacBio sequencing could generate much longer reads than SGS, the throughput is its weakness. There are 150,000 ZMWs on a single SMRT RSII cell, each of which could produce one polymerase read or CCS read. Typically, only 35,000~70,000 of 150,000 ZMWs on one cell could successfully produce reads due to either the failure to anchor a polymerase or loading more than one polymerase in a ZMW. Therefore, the typical throughput of the PacBio RS II system is about 0.5-1 billion bases (0.5-1 G) per SMRT cell (http://dnatech.genomecenter.ucdavis.edu/pacific-biosciences-rs/). With the advent of a new system called Sequel, the limitation to throughput has been much improved. Since the Sequel system could deliver over 7 times more reads with 1,000,000
