Experimental evidence indicating that mastreviruses probably did not co-diverge with their hosts

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dc.contributor.authorHarkins, Gordonen_ZA
dc.contributor.authorDelport, Wayneen_ZA
dc.contributor.authorDuffy, Siobainen_ZA
dc.contributor.authorWood, Natashaen_ZA
dc.contributor.authorMonjane, Aderitoen_ZA
dc.contributor.authorOwor, Bettyen_ZA
dc.contributor.authorDonaldson, Laraen_ZA
dc.contributor.authorSaumtally, Salemen_ZA
dc.contributor.authorTriton, Guyen_ZA
dc.contributor.authorBriddon, Roben_ZA
dc.contributor.authorShepherd, Dionneen_ZA
dc.contributor.authorRybicki, Edwarden_ZA
dc.contributor.authorMartin, Darrenen_ZA
dc.contributor.authorVarsani, Arvinden_ZA
dc.date.accessioned2015-10-30T09:30:51Z
dc.date.available2015-10-30T09:30:51Z
dc.date.issued2009en_ZA
dc.description.abstractBACKGROUND:Despite the demonstration that geminiviruses, like many other single stranded DNA viruses, are evolving at rates similar to those of RNA viruses, a recent study has suggested that grass-infecting species in the genus Mastrevirus may have co-diverged with their hosts over millions of years. This "co-divergence hypothesis" requires that long-term mastrevirus substitution rates be at least 100,000-fold lower than their basal mutation rates and 10,000-fold lower than their observable short-term substitution rates. The credibility of this hypothesis, therefore, hinges on the testable claim that negative selection during mastrevirus evolution is so potent that it effectively purges 99.999% of all mutations that occur. RESULTS: We have conducted long-term evolution experiments lasting between 6 and 32 years, where we have determined substitution rates of between 2 and 3 x 10-4 substitutions/site/year for the mastreviruses Maize streak virus (MSV) and Sugarcane streak Reunion virus (SSRV). We further show that mutation biases are similar for different geminivirus genera, suggesting that mutational processes that drive high basal mutation rates are conserved across the family. Rather than displaying signs of extremely severe negative selection as implied by the co-divergence hypothesis, our evolution experiments indicate that MSV and SSRV are predominantly evolving under neutral genetic drift. CONCLUSION: The absence of strong negative selection signals within our evolution experiments and the uniformly high geminivirus substitution rates that we and others have reported suggest that mastreviruses cannot have co-diverged with their hosts.en_ZA
dc.identifier.apacitationHarkins, G., Delport, W., Duffy, S., Wood, N., Monjane, A., Owor, B., ... Varsani, A. (2009). Experimental evidence indicating that mastreviruses probably did not co-diverge with their hosts. <i>Virology Journal</i>, http://hdl.handle.net/11427/14512en_ZA
dc.identifier.chicagocitationHarkins, Gordon, Wayne Delport, Siobain Duffy, Natasha Wood, Aderito Monjane, Betty Owor, Lara Donaldson, et al "Experimental evidence indicating that mastreviruses probably did not co-diverge with their hosts." <i>Virology Journal</i> (2009) http://hdl.handle.net/11427/14512en_ZA
dc.identifier.citationHarkins, G. W., Delport, W., Duffy, S., Wood, N., Monjane, A. L., Owor, B. E., ... & Varsani, A. (2009). Experimental evidence indicating that mastreviruses probably did not co-diverge with their hosts. Virol J, 6, 104.en_ZA
dc.identifier.ris TY - Journal Article AU - Harkins, Gordon AU - Delport, Wayne AU - Duffy, Siobain AU - Wood, Natasha AU - Monjane, Aderito AU - Owor, Betty AU - Donaldson, Lara AU - Saumtally, Salem AU - Triton, Guy AU - Briddon, Rob AU - Shepherd, Dionne AU - Rybicki, Edward AU - Martin, Darren AU - Varsani, Arvind AB - BACKGROUND:Despite the demonstration that geminiviruses, like many other single stranded DNA viruses, are evolving at rates similar to those of RNA viruses, a recent study has suggested that grass-infecting species in the genus Mastrevirus may have co-diverged with their hosts over millions of years. This "co-divergence hypothesis" requires that long-term mastrevirus substitution rates be at least 100,000-fold lower than their basal mutation rates and 10,000-fold lower than their observable short-term substitution rates. The credibility of this hypothesis, therefore, hinges on the testable claim that negative selection during mastrevirus evolution is so potent that it effectively purges 99.999% of all mutations that occur. RESULTS: We have conducted long-term evolution experiments lasting between 6 and 32 years, where we have determined substitution rates of between 2 and 3 x 10-4 substitutions/site/year for the mastreviruses Maize streak virus (MSV) and Sugarcane streak Reunion virus (SSRV). We further show that mutation biases are similar for different geminivirus genera, suggesting that mutational processes that drive high basal mutation rates are conserved across the family. Rather than displaying signs of extremely severe negative selection as implied by the co-divergence hypothesis, our evolution experiments indicate that MSV and SSRV are predominantly evolving under neutral genetic drift. CONCLUSION: The absence of strong negative selection signals within our evolution experiments and the uniformly high geminivirus substitution rates that we and others have reported suggest that mastreviruses cannot have co-diverged with their hosts. DA - 2009 DB - OpenUCT DO - 10.1186/1743-422X-6-104 DP - University of Cape Town J1 - Virology Journal LK - https://open.uct.ac.za PB - University of Cape Town PY - 2009 T1 - Experimental evidence indicating that mastreviruses probably did not co-diverge with their hosts TI - Experimental evidence indicating that mastreviruses probably did not co-diverge with their hosts UR - http://hdl.handle.net/11427/14512 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/14512
dc.identifier.urihttp://dx.doi.org/10.1186/1743-422X-6-104
dc.identifier.vancouvercitationHarkins G, Delport W, Duffy S, Wood N, Monjane A, Owor B, et al. Experimental evidence indicating that mastreviruses probably did not co-diverge with their hosts. Virology Journal. 2009; http://hdl.handle.net/11427/14512.en_ZA
dc.language.isoengen_ZA
dc.publisherBioMed Central Ltden_ZA
dc.publisher.departmentInstitute of Infectious Disease and Molecular Medicineen_ZA
dc.publisher.facultyFaculty of Health Sciencesen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.rightsThis is an Open Access article distributed under the terms of the Creative Commons Attribution Licenseen_ZA
dc.rights.holder2009 Harkins et al; licensee BioMed Central Ltd.en_ZA
dc.rights.urihttp://creativecommons.org/licenses/by/2.0en_ZA
dc.sourceVirology Journalen_ZA
dc.source.urihttp://www.virologyj.com/en_ZA
dc.subject.otherEvolution, Molecularen_ZA
dc.titleExperimental evidence indicating that mastreviruses probably did not co-diverge with their hostsen_ZA
dc.typeJournal Articleen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceArticleen_ZA
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