Fig. 4

Cluster analysis of acidic hot spring metagenomes. Based on COGs clustering, YNP and SHP were more similar to each other than NNPLN. Nonetheless, the functional profiles of the three metagenomes shared a high similarity (>80 %). The clustering result based on KEGG pathways was also consistent with this clustering result (Additional file 1: Figure S6). YNP, SHP, and NNPLN were metagenomes of Yellowstone National Park (USA), Shi-Huang-Ping (Taiwan) and National Natural Park Los Nevados (Colombia), respectively