AMPHORA2 uses 31 bacterial and 104 archaeal phylogenetic marker genes for inferring phylogenetic information from metagenomic datasets.
A candidate division, candidate phylum or candidate division-level is a lineage of Prokaryotic organisms for which no cultured representatives have been found, but evidence of the existence of the clade has been obtained by 16S rRNA metagenomic analysis of environmental samples.
Clardy is also known for his work in elucidating natural products made by unculturable bacteria and is credited, along with Jo Handelsman and Robert M. Goodman, for pioneering the field of metagenomics.