Robertson D L, Hahn B H, Sharp P M
Department of Genetics, University of Nottingham, Queens Medical Centre, United Kingdom.
J Mol Evol. 1995 Mar;40(3):249-59. doi: 10.1007/BF00163230.
Recombination contributes to the generation of genetic diversity in human immunodeficiency viruses (HIV) but can only occur between viruses replicating within the same cell. Since individuals have not been found to be simultaneously coinfected with multiple divergent strains of HIV-1 or HIV-2, recombination events have been thought to be restricted to the rather closely related members of the quasispecies that evolves during the course of HIV infection. Here we describe examples of both HIV-1 and HIV-2 genomes that appear to be hybrids of genetically quite divergent viruses. Phylogenetic analyses were used to examine the evolutionary relationships among multiple HIV strains. Evolutionary trees derived from different genomic regions were consistent with respect to most of the viruses investigated. However, some strains of HIV-1 and HIV-2 exhibited significantly discordant branching orders indicative of genetic exchanges during their evolutionary histories. The crossover points of these putative recombination events were mapped by examining the distribution of phylogenetically informative sites supporting alternative tree topologies. A similar example of a recombinant simian immunodeficiency virus identified in West African green monkeys has also been described recently. These results indicate that coinfection with highly divergent viral strains can occur in HIV-infected humans and SIV-infected primates and could lead to the generation of hybrid genomes with significantly altered biological properties. Thus, future characterization of primate lentiviruses should include careful phylogenetic investigation of possible genomic mosaicism.
重组有助于人类免疫缺陷病毒（HIV）产生遗传多样性，但只能在同一细胞内复制的病毒之间发生。由于尚未发现个体同时感染多种不同的HIV-1或HIV-2毒株，因此重组事件被认为仅限于在HIV感染过程中进化的准种中关系相当密切的成员之间。在此，我们描述了HIV-1和HIV-2基因组的一些例子，它们似乎是遗传上差异很大的病毒的杂交体。系统发育分析用于研究多种HIV毒株之间的进化关系。对于大多数所研究的病毒，来自不同基因组区域的进化树是一致的。然而，一些HIV-1和HIV-2毒株表现出明显不一致的分支顺序，这表明在它们的进化历史中发生了基因交换。通过检查支持替代树拓扑结构的系统发育信息位点的分布，绘制了这些假定重组事件的交叉点。最近也描述了在西非绿猴中鉴定出的重组猿猴免疫缺陷病毒的类似例子。这些结果表明，HIV感染的人类和SIV感染的灵长类动物可能会同时感染高度不同的病毒株，并可能导致产生具有显著改变的生物学特性的杂交基因组。因此，未来对灵长类慢病毒的特征描述应包括对可能的基因组镶嵌现象进行仔细的系统发育研究。
