Edwards Charles T T, Holmes Edward C, Wilson Daniel J, Viscidi Raphael P, Abrams Elaine J, Phillips Rodney E, Drummond Alexei J
Nuffield Department of Clinical Medicine, University of Oxford, The Peter Medawar Building for Pathogen Research, Oxford, OX1 3SY, UK.
BMC Evol Biol. 2006 Mar 23;6:28. doi: 10.1186/1471-2148-6-28.
Genetic diversity of the human immunodeficiency virus type 1 (HIV-1) population within an individual is lost during transmission to a new host. The demography of transmission is an important determinant of evolutionary dynamics, particularly the relative impact of natural selection and genetic drift immediately following HIV-1 infection. Despite this, the magnitude of this population bottleneck is unclear.
We use coalescent methods to quantify the bottleneck in a single case of homosexual transmission and find that over 99% of the env and gag diversity present in the donor is lost. This was consistent with the diversity present at seroconversion in nine other horizontally infected individuals. Furthermore, we estimated viral diversity at birth in 27 infants infected through vertical transmission and found there to be no difference between the two modes of transmission.
Assuming the bottleneck at transmission is selectively neutral, such a severe reduction in genetic diversity has important implications for adaptation in HIV-1, since beneficial mutations have a reduced chance of transmission.
人类免疫缺陷病毒1型（HIV-1）在个体内的种群遗传多样性在传播到新宿主的过程中会丧失。传播的人口统计学特征是进化动力学的一个重要决定因素，尤其是在HIV-1感染后自然选择和遗传漂变的相对影响。尽管如此，这种种群瓶颈的程度尚不清楚。
我们使用溯祖方法对一例同性恋传播案例中的瓶颈进行量化，发现供体中超过99%的env和gag多样性丧失。这与其他9例水平感染个体在血清转换时的多样性一致。此外，我们估计了27例通过垂直传播感染的婴儿出生时的病毒多样性，发现两种传播方式之间没有差异。
假设传播时的瓶颈是选择性中性的，遗传多样性如此严重的减少对HIV-1的适应性具有重要意义，因为有益突变的传播机会减少了。
