id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-002423-1u44tdrj	Geoghegan, Jemma L.	Comparative analysis estimates the relative frequencies of co-divergence and cross-species transmission within viral families	2017-02-08		.txt	text/plain	6186	267	44	While this method does not explicitly model host-switching events, it does provide a simple means to compare multiple topologies of virus-host pairs, and accounts for differences in sample size and the fact that several viruses from a specific family can infect a single host species. Across the data set as a whole we found that all virus families displayed relatively large tree topological distances with nPH85 values of !0.6, suggesting that cross-species transmission is widespread, at least at the family-level (Fig 2; S3 Table) . As with the analysis of topological distances, this revealed that cross-species transmission was the most common evolutionary event in all virus families studied here, with co-divergence consistently less frequent (with the possible exception of the Hepadnaviridae-see below), and lineage duplication and extinction playing a much more minor role. To investigate the comparative prevalence of cross-species transmission among viruses we measured the congruence between virus and host phylogenetic trees using a normalized tree topological distance-based approach (nPH85, [14] ).	./cache/cord-002423-1u44tdrj.txt	./txt/cord-002423-1u44tdrj.txt