Fig. 2
From: Genome sequence of walking catfish (Clarias batrachus) provides insights into terrestrial adaptation
Comparisons of genomic features of Clarias batrachus with those non-air-breathing fish species. a Schematic presentation of comparative genomic analyses of C. batrachus against non-air-breathing teleost fishes. In the catfish lineage, the protein sequences of the C. batrachus and I. punctatus genomes were comparatively subtracted, resulting in the identification of 1854 genes specific to the C. batrachus genome; similarly, 10 additional non-air-breathing fishes were added to compare with C. batrachus genome, resulting in the identification of 110 genes that were only present in the C. batrachus genome. The names of these 110 C. batrachus specific genes were searched with all existing sequences from non-air-breathing fish species in the NCBI database, resulting in no genes specific to the C. batrachus genome. b Comparison of the values of dN/dS ratio among various fish species against the ancestor estimated from 150 randomly picked single-copy genes with 10,000 bootstrap replicates. The red line represents the average dN/dS value in C. batrachus, noting that it is the second most rapidly evolving genome. c The number of gene families exhibiting expansion (red) / contraction (blue). C. batrachus is marked with red solid circle, showing that it has the largest number of expanded gene families. D. rerio, Danio rerio; G. aculeatus, Gasterosteus aculeatus; T. nigroviridis, Tetraodon nigroviridis; T. rubripes, Takifugu rubripes; O. latipes, Oryzias latipes; G. morhua, Gadus morhua; A. mexicanus, Astyanax mexicanus; O. niloticus, Oreochromis niloticus; X. maculatus, Xiphophorus maculatus; P. formosa, Poecilia formosa; I. punctatus, Ictalurus punctatus