Conservation Research Section, Senckenberg Research Institutes and Natural History Museums, Clamecystrasse 12, D-63571 Gelnhausen, Germany.
Chemosphere. 2012 Aug;88(8):988-93. doi: 10.1016/j.chemosphere.2012.03.036. Epub 2012 Apr 3.
We report results of a multigenerational experiment with Chironomus riparius. Two strains with a high and a low level of genetic variability were exposed to a low, environmentally relevant TBT concentration of 80 μg Sn kg(-1)sedimentdw nominally (time weighted mean, based on measured concentrations: 4.5 μg Sn kg(-1)sedimentdw), and various life history traits as well as genetic diversity were monitored for eleven consecutive generations. While TBT effects are hardly visible in the outbred and genetically diverse strain, the inbred and genetically impoverished strain shows a clearly reduced population growth rate compared to the control. Moreover, the impoverished strain shows an increase in fitness over time. Analyses of variation at five microsatellite loci revealed that the level of genetic variation is strongly reduced in the inbred compared to the outbred strain. Moreover, genetic diversity increases over time in the inbred strain. This finding explains the observed increase in fitness in both inbred lineages (control and TBT exposed). The results document that inbreeding and the level of genetic diversity might be of crucial importance in populations under pollution stress. Furthermore, ecotoxicological bioassays have to consider genetic diversity if results between laboratories should be comparable. Our data provides evidence that genetic diversity strongly contributes to the survival of a population exposed to chemical pollution.
我们报告了一个关于摇蚊的多世代实验结果。两个遗传变异性高低不同的种群暴露于一个低浓度的、环境相关的 TBT 浓度（基于测量浓度的名义浓度，即 80μgSnkg(-1) 沉积物 dw，时间加权平均值：4.5μgSnkg(-1) 沉积物 dw），监测了十一个连续世代的各种生活史特征和遗传多样性。虽然 TBT 对杂种和遗传多样性丰富的种群几乎没有影响，但与对照相比，自交和遗传贫瘠的种群的种群增长率明显降低。此外，贫瘠的种群的适合度随时间增加。对五个微卫星位点的变异分析表明，与杂种种群相比，自交种群的遗传变异水平显著降低。此外，自交种群的遗传多样性随时间增加。这一发现解释了在两个自交系（对照和 TBT 暴露）中观察到的适合度增加。研究结果表明，在污染压力下的种群中，近交和遗传多样性水平可能至关重要。此外，如果要使实验室之间的结果具有可比性，生态毒理学生物测定必须考虑遗传多样性。我们的数据提供了证据，证明遗传多样性对暴露于化学污染的种群的生存具有重要贡献。
