id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-022336-zqnczjpp	Robertson, Hugh D.	Virus Origins: Conjoined RNA Genomes as Precursors to DNA Genomes	2007-09-02		.txt	text/plain	6163	229	47	The chapter also outlines the significance of work on viroid-like pathogens, circular RNA replication, and their potential relation to early RNA; and relates the early emergence of RNA mosaics to developments leading to today's DNA-based systems of viral gene expression. Recent work to be reviewed below shows that there is one class of primitive life forms-the viroid-like pathogens -whose properties today could help us to understand how primitive RNA-based self-replication may have been compatible with expansion to produce more complex RNAs. In summary, the causative agent for human hepatitis delta contains two specialized domains, one concerned with replication and the other encoding a single protein (Branch et al., 1989; Purcell and Gerin, 1996; Taylor, 1996) . It is evident that if RNA conjunction leading to delta-like RNA mosaics with both replicating and functionally translatable protein-coding domains has taken place, we need to consider the consequences both for the evolution of primitive RNA systems, yielding today's DNA-based cellular information system, and for presentday RNA-level events.	./cache/cord-022336-zqnczjpp.txt	./txt/cord-022336-zqnczjpp.txt