Oh, I got it. Actually, a heat map coupled with phylogeny (hierarchical relationships) is called an interactive heat map and that specific network is called a "dataframe". Here each line is representing one gene. The whole network is similar to that of a phylogenetic tree, however here the relationship is decided by gene ontology, not by genetic distance. In other words, the lines having common branches are showing similar types of gene ontology and vice versa.
