编辑“︁病毒”︁（章节）

=== 遗传变异 ===
{{Image|zh-hans=Influenza geneticshift zh.jpg|zh-hant=Influenza geneticshift zh-hant.jpg|thumb|200px|left|基因重配（reassortment）是“抗原转变”的一类机制。此图显示两个不同的流感病毒株如何透过重配形成新的病毒株。}}
病毒的遗传变异可以有多种机制。[[抗原漂變]]（antigenic drift）是其中之一，即病毒DNA或RNA上单个[[核鹼基|碱基]]的[[突变]]。大多数这样的单点突变是无义的（或者说是沉默的），因为它们没有导致所编码的蛋白质发生变化；但有一小部分突变可能会引起进化上的优势，如产生对[[抗病毒药物]]的抵抗力。<ref name="pmid17927612">{{Cite journal |last=Pan |first=X. P. |last2=Li |first2=L. J. |last3=Du |first3=W. B. |last4=Li |first4=M. W. |last5=Cao |first5=H. C. |last6=Sheng |first6=J. F. |title=Differences of YMDD mutational patterns, precore/core promoter mutations, serum HBV DNA levels in lamivudine-resistant hepatitis B genotypes B and C |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1365-2893.2007.00869.x |journal=Journal of Viral Hepatitis |language=en |date=2007 |volume=14 |issue=11 |doi=10.1111/j.1365-2893.2007.00869.x |issn=1365-2893 |access-date=2025-02-06 |archive-date=2023-09-06 |archive-url=https://web.archive.org/web/20230906193419/https://onlinelibrary.wiley.com/doi/10.1111/j.1365-2893.2007.00869.x |dead-url=no }}</ref>[[抗原轉變]]（antigenic shift）则是病毒基因组的较重大变化，其为[[基因重组]]<ref>{{Cite web |title=术语在线 |url=https://www.termonline.cn/word/100902/1#s1 |website=www.termonline.cn |access-date=2025-02-06 |archive-date=2021-12-24 |archive-url=https://web.archive.org/web/20211224005204/https://www.termonline.cn/word/100902/1#s1 |dead-url=no }}</ref>（recombination）或[[基因重配]]<ref>{{Cite web |title=术语在线 |url=https://www.termonline.cn/word/1275259046319898629/1#s1 |website=www.termonline.cn |access-date=2025-02-06 |archive-date=2021-12-24 |archive-url=https://web.archive.org/web/20211224005232/https://www.termonline.cn/word/1275259046319898629/1#s1 |dead-url=no }}</ref>（reassortment）的结果。当[[流行性感冒病毒|流感病毒]]发生抗原转变后，可能会导致[[瘟疫]]。<ref name="pmid17115950">{{Cite journal |last=Hampson |first=Alan W |last2=Mackenzie |first2=John S |title=The influenza viruses |url=https://onlinelibrary.wiley.com/doi/full/10.5694/j.1326-5377.2006.tb00705.x |journal=Medical Journal of Australia |language=en |date=2006 |volume=185 |issue=S10 |doi=10.5694/j.1326-5377.2006.tb00705.x |issn=1326-5377 |access-date=2025-02-06 |archive-date=2023-04-15 |archive-url=https://web.archive.org/web/20230415075318/https://onlinelibrary.wiley.com/doi/full/10.5694/j.1326-5377.2006.tb00705.x |dead-url=no }}</ref>

RNA病毒常常以[[准种]]（quasispecies）的形式或大量同种但基因组核苷酸序列存在微小差异的病毒的形式存在。这样的准种是自然选择的主要目标。<ref name="pmid17578210">{{Cite journal |last=Metzner |first=Karin J. |title=Detection and significance of minority quasispecies of drug-resistant HIV-1 |url=https://pubmed.ncbi.nlm.nih.gov/17578210/ |journal=Journal of HIV therapy |date=2006-12 |volume=11 |issue=4 |issn=1462-0308 |pmid=17578210 |access-date=2025-02-06 |archive-date=2025-03-18 |archive-url=https://web.archive.org/web/20250318202138/https://pubmed.ncbi.nlm.nih.gov/17578210/ |dead-url=no }}</ref>

==== 抗原转变的两类机制 ====
* 基因重配：分节的基因组具有进化上的优势，因为同一种病毒的不同的病毒株中的节段基因组可以进行基因移位及组配，重配后产生的后代病毒具有不同于上一代的独特的特征。这种基因重配又称为“病毒的有性生殖”（''viral sex''）。<ref>Goudsmit, Jaap. Viral Sex. Oxford Univ Press, 1998.ISBN 9780195124965</ref>

* 基因重组：在不同的两条或两条以上病毒核酸链间，或同一条病毒核酸链的不同区域内，发生了遗传-{信息}-的重新组合，而产生一条嵌合的重组核酸链。基因重组可以在病毒感染细胞的同时发生。对[[病毒进化]]的研究结果显示，在已研究的各种病毒中，重组发生得极为频繁。<ref name="pmid10573145">{{Cite journal |last=Worobey |first=Michael |last2=Holmes |first2=Edward C. |title=Evolutionary aspects of recombination in RNA viruses |url=https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-80-10-2535 |journal=Journal of General Virology |language=en |date=1999-10-01 |volume=80 |issue=10 |doi=10.1099/0022-1317-80-10-2535 |issn=0022-1317 |access-date=2025-02-06 |archive-date=2025-06-20 |archive-url=https://web.archive.org/web/20250620174449/https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-80-10-2535 |dead-url=no }}</ref>而且，无论是RNA病毒还是DNA病毒，重组的发生都是非常普遍的。<ref name="pmid15578739">{{Cite journal |last=Lukashev |first=Alexander N. |title=Role of recombination in evolution of enteroviruses |url=https://onlinelibrary.wiley.com/doi/10.1002/rmv.457 |journal=Reviews in Medical Virology |language=en |date=2005 |volume=15 |issue=3 |doi=10.1002/rmv.457 |issn=1099-1654 |access-date=2025-02-06 |archive-date=2025-07-08 |archive-url=https://web.archive.org/web/20250708092133/https://onlinelibrary.wiley.com/doi/10.1002/rmv.457 |dead-url=no }}</ref><ref name="pmid10479778">{{Cite journal |last=Umene |first=Kenichi |title=Mechanism and application of genetic recombination in herpesviruses |url=https://onlinelibrary.wiley.com/doi/10.1002/(SICI)1099-1654(199907/09)9:3%3C171::AID-RMV243%3E3.0.CO;2-A |journal=Reviews in Medical Virology |language=en |date=1999-07 |volume=9 |issue=3 |doi=10.1002/(SICI)1099-1654(199907/09)9:3<171::AID-RMV243>3.0.CO;2-A |issn=1052-9276 |access-date=2025-02-06 |archive-date=2023-11-26 |archive-url=https://web.archive.org/web/20231126030517/https://onlinelibrary.wiley.com/doi/10.1002/(SICI)1099-1654(199907/09)9:3%3C171::AID-RMV243%3E3.0.CO;2-A |dead-url=no }}</ref>