The origin of viruses from cells.
D001419:Bacteria; D001483:Base Sequence; D005075:Biological Evolution; D002689:Chlamydia; D004261:DNA Replication; D004251:DNA Transposable Elements; D004279:DNA, Viral; D005814:Genes, Viral; D009154:Mutation; D010957:Plasmids; D012326:RNA Splicing; D012367:RNA, Viral; D011995:Recombination, Genetic; D014779:Virus Replication; D014780:Viruses
D004251:DNA Transposable Elements; D004279:DNA, Viral; D012367:RNA, Viral