Testing for population differences in evolutionary responses to pesticide pollution in brown trout (Salmo trutta)

Pesticides are often toxic to non-target organisms, especially to those living in rivers that drain agricultural land. The brown trout (Salmo trutta) is a keystone species in many such rivers, and natural populations have hence been chronically exposed to pesticides over multiple generations. The introduction of pesticides decades ago could have induced evolutionary responses within these populations. Such a response would be predicted to reduce the toxicity over time but also deplete any additive genetic variance for the tolerance to the pesticides. If so, populations are now expected to differ in their susceptibility and in the variance for the tolerance depending on the pesticides they have been exposed to. We sampled breeders from seven natural populations that differ in their habitats and that show significant genetic differentiation. We stripped them for their gametes and produced 118 families by in vitro fertilization. We then raised 20 embryos per family singly in experimentally...农药通常对非靶标生物（non-target organisms）具有毒性，尤以承接农业用地径流的河流中的生物为甚。褐鳟（Salmo trutta）是众多此类河流中的关键物种（keystone species），因此其野生种群长期持续多代暴露于农药环境中。数十年前投入使用的农药或已在这些种群中诱发进化响应。此类响应理论上会随时间推移降低农药的毒性，但同时也会耗尽种群对农药耐受性的加性遗传方差（additive genetic variance）。若该推测成立，则当前不同种群的易感性及耐受性方差，应会因各自所暴露的农药环境而异。本研究从7个生境存在差异、且遗传分化显著的野生种群中采集繁殖亲本。通过人工挤取亲本配子，经体外受精（in vitro fertilization）构建了118个家系。随后我们将每个家系的20枚胚胎单独饲养于实验条件下……