Brown A J
Centre for HIV Research, Institute of Cell, Animal and Population Biology, University of Edinburgh, Scotland.
Proc Natl Acad Sci U S A. 1997 Mar 4;94(5):1862-5. doi: 10.1073/pnas.94.5.1862.
Selection is usually considered to be the dominant force controlling viral variation; the large population sizes suggest that deterministic population genetic models are appropriate. To investigate their validity for HIV, samples of env gene sequences were tested for departure from neutrality because of mutation-selection balance. None of the samples departed significantly when tested as nucleotide sequences. At the amino acid level, significantly elevated diversity was detected in two samples within, but not outside, the V3 loop. The effective population number has been estimated (using a phylogenetic method) to be close to 10(3). Estimates from nucleotide diversity are about 2-fold lower. The low value of the effective population number might arise from high variability in progeny number between infected cells, from the expansion in population number from a small inoculum as the virus is transmitted between hosts, or from variable selection at linked sites. These results suggest that the population genetics of HIV are best described by stochastic models.
选择通常被认为是控制病毒变异的主导力量；庞大的种群规模表明确定性种群遗传模型是适用的。为了研究这些模型对HIV的有效性，对env基因序列样本进行了测试，以检验由于突变-选择平衡而偏离中性的情况。当作为核苷酸序列进行测试时，没有一个样本出现显著偏离。在氨基酸水平上，在V3环内部的两个样本中检测到显著升高的多样性，但在V3环外部未检测到。（使用系统发育方法）估计有效种群数量接近10³。从核苷酸多样性得出的估计值大约低2倍。有效种群数量较低可能是由于受感染细胞之间子代数量的高度变异性、病毒在宿主之间传播时从小接种量开始的种群数量扩张，或者是由于连锁位点的可变选择。这些结果表明，HIV的种群遗传学最好用随机模型来描述。
