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, nature research | reporting summary, 2018.

. Gb_files_inoviruses and . Zip, GenBank files of all representative genomes for each inovirus species. Ref_PCs_inoviruses.zip: Protein clusters from the references (raw fasta, alignment fasta, hmm profile). iPFs_inoviruses.zip: Protein families from extended inovirus dataset (raw fasta, alignment fasta

. Mobm_c_primer_amplicon and . Fasta, Multiple sequence alignment of the C primer products with Methanolobus MobM genome, p.1000007

, No sample size calculation was performed, as the largest collection of publicly available data possible was mined. Data exclusions No data were excluded

, This includes PCR amplification of the putative archaeal inovirus provirus, which was repeated either two of three times with similar results (see Supplementary Fig. 11), and the superinfection experiments which were conducted twice and produced similar results

, Randomization None of the analyses involved allocation of samples to different groups. Blinding None of the analyses required blind investigation since the study does not involve a treatment vs control trial (with the exception of "obvious

, Reporting for specific materials, systems and methods

, We require information from authors about some types of materials, experimental systems and methods used in many studies. Here, indicate whether each material, system or method listed is relevant to your study