Fig. 4: Expanding delta viruses and huge phages.
From: Petabase-scale sequence alignment catalyses viral discovery
a, Genome structure for the Marmota monax delta virus (MmonDV) and a delta-virus-like genome detected in an environmental dataset, each containing a negative-sense delta-antigen (δAg) ORF; two delta ribozymes (drbz); and characteristic rod-like folding, where each line shows the predicted base-pairing within the RNA genome, coloured by base-pairing confidence score (p-num)50. b, Similar genome structure for the Sulabanus spp. epsilon virus-like (SulaEV) and an epsilon-virus-like genome from an environmental dataset, each containing a negative-sense epsilon-antigen (εAg) ORF; two hammerhead ribozymes (hhrbz); and rod-like folding. c, Example of the compact genome structure of a Zeta virus-like from an environmental dataset containing two predicted zeta-antigen (ζAg+/−; protein alignment is shown in the outer circles) ORFs without stop codons; two hhrbzs overlapping with the ORFs; and rod-like folding. Further novel genomes are shown in Extended Data Figs. 5, 6. d, Maximum-likelihood phylogenetic tree of delta viruses derived from a delta-antigen protein alignment with bootstrap values. Two divergent environmental delta viruses could not yet be placed. e, Tree showing huge phage clade expansion. Black dots indicate branches with bootstrap values greater than 90. Outer ring indicates genome or genome fragment length: grey are sequences from Al-Shayeb et al.42 and reference sequences, shadings indicate previously defined clades of phages with very large genomes (200–735 kb). The Kabirphages (light purple) are shown in expanded view in Extended Data Fig. 7.
