生物的变异是生物为适应环境的不断变化,维持生存和种族繁衍的需要而采取的一种十分重要和必要的应对措施。病毒也广泛存在和不断发生变异,尤其是RNA病毒,如HCV、HIV等。DNA病毒也可发生变异,尤其是HBV,其在复制过程中缺乏校对功能。HBV的变异率高于其它DNA病毒约4个数量级,但低于RNA病毒1～2个数量级。HBV的复制效率非常高,每天可生成 Biological variation is a very important and necessary response for living organisms to adapt to the changing environment, the need to survive and to race. Viruses are also widespread and constantly evolving, especially RNA viruses such as HCV, HIV and the like. DNA viruses can also mutate, especially HBV, which lacks proofreading in the replication process. The mutation rate of HBV is about 4 orders of magnitude higher than that of other DNA viruses, but it is lower than that of RNA viruses by 1 to 2 orders of magnitude. HBV replication is very efficient and can be generated daily