Fig. 1.

Length of 3’ UTRs in nine teleost fishes. a Phylogenetic tree of the focal nine teleost fishes with time-scale according to estimated divergence time from TimeTree [66]. The five species in red are cichlid species and the four species in purple are other model teleosts. b Frequency distribution of 3’ UTR length of nine teleost fishes for 2041 1:1 orthologous genes. In cichlids, there are fewer 3’UTRs that are shorter than the median length and more 3’UTRs that are longer than the median length. c Comparison of 3’ UTR length between cichlids and non-cichlids. The ratios of the mean length of 3’ UTR in cichlids to that in non-cichlids are calculated for 1:1 orthologous genes. These ratios were log₁₀-transformed. In general, cichlids have longer 3’ UTRs than non-cichlids (one-sample t-test that the mean log₁₀ ratio = 0.0; p <  0.001). The top 5% relatively longest 3’ UTRs in cichlids taken from these 2041 orthologous genes were further analyzed for enrichment of gene functions (GO terms and KEGG pathways). The images of A. mexicanus, O. latipes, O. niloticus, M. zebra, N. brichardi and P. nyererei were taken from Wikimedia Commons (http://commons.wikimedia.org/wiki/), while the images of H. burtoni, D. rerio and P. formosa were taken from FishBase (http://www.fishbase.org)