Fig. 4From: A comparative study of ammonia-oxidizing archaea and bacteria in acidic and alkaline purple soils a Neighbor-joining phylogenetic tree of AOA amoA sequences retrieved from the ACI and ALK libraries. Filled circles (red ACI, blue ALK) Sequence numbers from this study, open black triangles reference sequences. Bootstrap values (>50) are indicated at branch points. Scale bar represents 5Â % estimated sequence divergence. b The composition analysis of the archaeal amoA gene in the ALK (a) and ACI (b) librariesBack to article page