Fig. 1: Genome of the inshore hagfish, E. burgeri.

a, Dorsal view of a young adult of the inshore hagfish E. burgeri, with the head to the top right. The teeth apparatus (and not a jaw) can be observed in a magnification of the head region of a fixed adult individual (a’). b, Fertilized egg of E. burgeri with a developing embryo at stage Dean 53 (ref. ⁴⁸). Blood vessels can be observed from the exterior. c, Two competing hypotheses of vertebrate phylogeny. WGD events corresponding to the 2R hypothesis (lilac), to an alternative vertebrate 2R hypothesis (orange) and to those recently proposed in the lamprey lineage (light blue) are marked. Whether the lamprey-specific events actually occurred in a stem cyclostome remains elusive. d, Hi-C contact heatmap of the corrected hagfish genome assembly ordered by cluster (chromosome) length. Dashed boxes indicate the cluster boundaries. e, Completeness assessment of the genome assembly of the inshore hagfish E. burgeri genome (red), three lamprey species (blue) and two jawed vertebrates (green). Number of conserved metazoan orthologues (metazoa_odb10 dataset, containing 954 BUSCOs) is indicated for each case. F. E., Far Eastern. f, Correspondence analysis (CoA) on RSCU values was performed using the nucleotide sequences of all predicted genes concatenated for individual species. The percentage of variance is indicated for each axis. g, CoA of amino acid composition, with the percentage of variance indicated for each axis. In f and g: red, hagfish; blue, lamprey; green, jawed vertebrates; black, invertebrates.