Identification and ecological assessment of environmental stressors on fish population using genetic biomarkers

为了鉴定和评价环境胁迫因素对各种群的影响，对不同地点采集的假青鱼（Pseudorasbora parvac）种群遗传生物标志物的差异进行了分析。首先，研究了扩增片段长度多态性（AFLP）方法在鱼类中的应用，以获得鱼类种群间遗传变异的可靠数据，并发现二维数据（荧光强度与基因片段长度）的测量可用于此目的。在过去经历过大量鱼类死亡的parvac伪藻种群中，用所提出的方法测量的遗传变异性与从其他栖息地获取的种群相比较小。此外，通过AFLP方法分类的每个种群中不同基因型的组成对于那些生活在受特殊环境压力因素（如隔离或农业废水的农用化学品影响）影响的地点的种群是特殊的。此外，多环芳烃（PAHs）污染还与各鱼类种群中不同基因型的组成有关。换句话说，较高的多环芳烃浓度增加了每个鱼种群中某种基因型的组成。不同生境的鱼类对多环芳烃中主要应激源氟蒽的急性毒性(50%致死浓度（LC_<50>）和50%有效浓度（EC_<50>）存在显著差异。说明各生境环境对荧光蒽的污染程度不同，对荧光蒽的耐受性也不同。本研究表明，利用AFLP方法测定的遗传变异和基因型可用于鉴定和评价环境胁迫对鱼类种群的影响。

Difference of genetic biomarkers among fish (Pseudorasbora parvac) populations collected from various sites was examined in order to identify and assess the environmental stressors on each population. First, application of Amplified Fragment Length Polymorphism (AFLP) method to fish was studied for obtaining reliable data on genetic variability among fish populations and measurement of two-dimensional data (strength of fluorescence vs. length of gene fragment) was found to be acceptable for this purpose.The genetic variability measured by the proposed method in Pseudorasbora parvac population which experienced large fish kill in the past was small compared to those taken from other habitats. Also the composition of different genotypes in each population classified by AFLP method was found to be special for those populations that live in sites impacted by special environmental stressors such as isolation or agrochemical impact from agricultural effluent. Furthermore, the pollution by polycyclic aromatic hydrocarbons (PAHs) was found to be related to the composition of different genotypes in each fish population. In other words, higher concentration of PAHs increased the composition of a certain genotype in each fish population. The acute toxicity (50% lethal concentration (LC_<50>) and 50% effective concentration (EC_<50>)) of Pseudorasbora parvac to fluoranthene, which was indicated to be the main stressor among PAHs, was significantly different among the fish populations taken from different habitats. This indicated that tolerance of Pseudorasbora parvac to luoranthene was varied due to the difference of environmental fluoranthene pollution in each habitat.This study showed that genetic variability and genotype measured by AFLP method can be used to identify and assess the environmental stressors to fish population.