
CLIP target site evolution. (A) The conservation of target sites in 10 species of mammals which are compared with human. (B) The conservation of randomly selected 6-mer sites in 3′ UTRs. The x-axis indicates the number of nonhuman species in which the sites are conserved. (C) The observed and expected proportions of sites that are conserved between human and other vertebrates. The divergence times between human and one of the other selected species are shown in parentheses.











