“…One category is the taxonomy-dependent methods (Brady and Salzberg, 2009;Haque et al, 2009;Huson et al, 2007;Krause et al, 2008;Matsen et al, 2010;McHardy et al, 2007;Meyer et al, 2008;Mohammed et al, 2011;Stark et al, 2010;Wood and Salzberg, 2014;Wu and Eisen, 2008), which compare reads with sequences in public databases or models inferred from public databases to group reads and determine which known species are present. The other category is the taxonomy-independent methods (Chatterji et al, 2008;Diaz et al, 2009;Wang et al, 2012Wang et al, , 2015Wu and Ye, 2011), which employ the difference of GC content (guanine-cytosine content), k-mer (a k base pairs long DNA segment) frequencies, etc., of different microbes in the same samples to bin reads.…”