Fig. 1

Presentation of the reference genome assemblies. A Channel catfish (Ictalurus punctatus) assembly Coco_2.0 with 29 chromosomes: Centromere positions are denoted by red triangles, telomere presence is denoted by a blue cap, and sequence gaps are denoted by black lines. B Blue catfish (I. furcatus) assembly Billie_1.0 with 29 chromosomes; annotated as above. The chromosome length is scaled in megabases. For both A and B, chromosomes are presented with the centromeres in the upper half of the chromosomes, including those of chromosomes 6, 11, and 24 where pericentric inversions are present between the two species. Concordance of marker positions on the genome sequences and genetic maps of channel catfish (C) and blue catfish (D) are presented as plot of chromosome physical length (x-axis) versus genetic distance (y-axis). E Circos presentation of the linear relationships between the channel catfish and blue catfish genomes, with GC content (track a), repeat elements density (track b), gene density (track c), and the collinearity of protein-coding genes (track d). F Dot plot of MUMmer whole-genome sequence alignments of the channel catfish (x-axis) versus blue catfish (y-axis) chromosomes