Distribution of all the singletons and clustered genes from the various human C2H2-ZNF sub-families and gene composition of the C2H2-ZNF clusters. A) The number of genes belonging to the various C2H2-ZNF subfamilies are shown as well as the proportion of genes found as singletons or as part of clusters. C2H2-ZNF genes associated with KRAB and SCAN domains are more often found to be clustered. S-K = C2H2-ZNF containing both a SCAN and a KRAB domain. NONE = C2H2-ZNF without any conserved domain associated. The percentage distribution is mentioned on top of each bar for each sub-family. B) The number of C2H2-ZNF clusters is shown with respect to the number of genes present in each cluster. The proportion of clusters composed solely of C2H2-ZNF without any intervening gene or with intervening genes other than C2H2-ZNF (Non-C2H2-ZNF) is also represented. An asterisk identifies large clusters present on human chromosome 19.