The Widespread Evolutionary Significance of Viruses

Epidemiological correlation between COVID-19 epidemic and prevalence of α-1 antitrypsin deficiency in the world

“…It appeared that the mutant had an advantage in propagation on account of the reduced pathogenicity that permitted persistence in the host (16). It should be recalled that persistence is one of the important characteristics for successful propagation of viruses among hosts (18). Recently, attenuated variants of SARS-CoV-2 were obtained, which had a deletion in ORF7b and ORF8 (19,20) or in S1/S2 junction (21).…”

Introduction to Virus Origins and Their Role in Biological Evolution

“…From the catalogs of regulatory sequences and proteincoding genes from cellular organisms and viruses whose functions have been identified, some viral genes, notably those encoding the viral capsid and the genome packaging machinery, appear to be devoid of a cellular counterpart. Comparative genomics suggests that the exchange of functional and structural modules through lateral gene transfers, together with fine adjustments mediated by mutation, have contributed to the coadaptation of cells and autonomous replicons over ancient evolutionary periods (Gorbalenya, 1995;Holland and Domingo, 1998;Jalasvuori and Bamford, 2008;Villarreal, 2008). Other viral functions do not deviate in any salient way from cellular functions.…”

“…The evolved viruses acted as selective agents to promote microbial evolution and then became established in an increasingly differentiated cellular world (Villarreal, 2005(Villarreal, , 2008Hendrix, 2008;Jalasvuori and Bamford, 2008). Their transfer to lower temperatures might have modulated their permeability prior to the stage at which peptide or protein transporters were inserted as membrane components.…”

“…Viruses might have contributed to the DNA replication machinery of cells, to the formation of the eukaryotic cell nucleus, and to a number of developmental processes (Baranowski et al, 2001;Bushman, 2002;Bacarese-Hamilton et al, 2004;Mallet et al, 2004;Villarreal, 2005Villarreal, , 2008Forterre, 2006a). Once the instruction to replicate had been positively selected, selfish elements could ensue.…”

“…Replication-competent, cytopathic variants of bovine viral diarrhea virus (a type species of the genus Pestivirus of the important family of pathogens Flaviviridae) can acquire cellular mRNA sequences in their genome, via nonhomologous recombination (Meyers et al, 1989). The existence of alternative mechanisms for the integration of viral genetic material into cellular DNA suggests an ancient origin and a selective advantage of exchanges of genetic information in shaping a diverse and adaptable cellular world (Eigen, 1992(Eigen, , 2013Gibbs et al, 1995;Villarreal, 2005Villarreal, , 2008. Some defective-interfering particles of Sindbis virus included cellular tRNA sequences at their 5′-ends (Monroe and Schlesinger, 1983).…”