Editing Parvoviridae (section)

==Evolution==
Parvoviruses are believed to be descended from ssDNA viruses that have a circular genome that forms a loop and which replicate via [[rolling circle replication]], which is similar to rolling hairpin replication. These circular ssDNA viruses encode a replication initiator protein that is related to and possesses many of the same characteristics as the replication initiator protein of parvoviruses, such as the HUH endonuclease domain and the SF3 helicase domain.<ref name=mono >{{cite web |vauthors=Koonin EV, Dolja VV, Krupovic M, Varsani A, Wolf YI, Yutin N, Zerbini M, Kuhn JH |title=Create a megataxonomic framework, filling all principal taxonomic ranks, for ssDNA viruses |url=https://ictv.global/ictv/proposals/2019.005G.zip |publisher=ICTV |access-date=24 January 2021 |format=docx |date=18 October 2019}}</ref> In contrast to these other replication initiator proteins, NS1 shows only vestigial traces of being able to perform ligation, which is a key part of rolling circle replication.{{sfn|Kerr|Cotmore|Bloom|2005|p=175}} The ''[[Bidnaviridae]]'' family, which are also linear ssDNA viruses, appear to be descended from a parvovirus that had its genome integrated into the genome of a [[polinton]], a type of DNA [[transposon]] related to viruses in the realm ''[[Varidnaviria]]''.<ref name=mono />

Based on phylogenetic analysis of the SF3 helicase, parvoviruses split into two branches early in their evolutionary history, one of which contains viruses assigned to the subfamily ''Hamaparvovirinae''. The other branch split into two sublineages that constitute the other two subfamilies, ''Densovirinae'' and ''Parvovirinae''.<ref name=parvo2019 >{{cite web |url=https://ictv.global/ictv/proposals/2019.010D.zip |title=Re-organize the family ''Parvoviridae'' |vauthors=Penzes JJ, Soderlund-Venermo M, Canuti M, Eis-Huebinger AM, Hughes J, Cotmore SF |publisher=ICTV |format=docx |access-date=24 January 2021}}</ref> Parvoviruses in the ''Hamaparvovirinae'' lineage are likely all heterotelomeric, ''Densovirinae'' are exclusively homotelomeric, and ''Parvovirinae'' varies.<ref name=cotmoreictv /> Telomere sequences have significant complexity and diversity, suggesting that many species have co-opted them to perform additional functions.<ref name=cotmore1996 />{{sfn|Kerr|Cotmore|Bloom|2005|p=173}} Parvoviruses are also considered to have high rates of genetic [[mutation]]s and [[Genetic recombination|recombinations]].<ref name=cotmoreictv /><ref name=martin />