Can roach, Rutilus rutilus, adapt to the harmful effects of oestrogen exposure from waste water treatment work effluents?

全世界的注意力主要集中在观察到野生动物和人类种群的生殖中断，这可能是由于接触干扰人体激素信号系统的化学品（所谓的内分泌干扰化学品; EDCs）对生殖健康产生影响。我们已经证明，生活在英国许多河流中的鱼类（蟑螂，鲤鱼家族的常见成员）的繁殖受到了废水处理厂（WwTW）流出物中所含内分泌干扰物的破坏，造成这些影响的化学物质包括天然雌激素和避孕药中的药物雌激素。雌性化的蟑螂在竞争性繁殖条件下繁殖的能力降低，我们有证据（尚未发表）表明生活在污水含量高的河流中的野生蟑螂繁殖种群规模减少。繁殖个体数量少的种群在多代中失去遗传变异，灭绝的风险更大。尽管如此，我们发现，在这些河流的某些延伸与高雌激素暴露蟑螂种群似乎是生殖自我维持。确定鱼是否（这里是蟑螂）已经适应了雌激素污染物，他们是如何做到这一点（机制）和这些适应的可能适应成本对于理解适应力至关重要（以及可持续性）的鱼类种群生活在这些污染的环境中。我们将研究是否蟑螂种群暴露于雌激素WwTW污水在多个世代已导致遗传选择和选择的影响，雄鱼对雌激素诱导的影响的敏感性与负面的健身后果有关。我们将通过识别它们的遗传组成中功能上的显著变化来研究选择。具体来说，我们将寻找遗传多态性（所谓的单核苷酸多态性-SNP）的差异，（1）我们知道在生殖（和其他生命）过程的雌激素信号传导中很重要的特定（候选）基因，以及（2）通过使用允许我们扫描整个基因组的方法（使用称为RAD标签基因分型的技术）。采用这些方法，我们希望找到“足迹”的选择生活在河流中的鱼类具有较高的雌激素污水含量，这应该允许识别新的适应过程，并提出重要的机制，毒性或在污水丰富的环境中生存。独特的是，我们能够做这项工作，因为我们有深入的知识，（15年研究）我们将通过比较几代暴露于高水平雌激素流出物的蟑螂种群是否已经适应对环境雌激素的反应变得不那么敏感，因此现在对它们的相关不利影响不那么敏感。对避孕雌激素炔雌醇的反应。我们将使用从与上述种群遗传分析相同的清洁和WwTW污水污染场地收集的蟑螂，鱼类将暴露1年，并量化对雄鱼（包括卵睾）具有负面健身后果的反应的影响。这项工作的目的是大大提高鱼类适应暴露于环境污染物（这里雌激素）的能力，以及它们是如何做到这一点的理解，反过来又有助于了解英国河流中接受WwTW污水排放的鱼类种群弹性。这项工作对规管污水排放，以更有效地保护本港的水生资源和生物多样性，至为重要，并会引起政府规管机构、环保团体、业界和广大市民的广泛关注。

Major worldwide attention has focused on the observations of disruptions of reproduction in both wildlife and human populations that can result from exposure to chemicals that interfere with the body's hormone signalling systems (so-called endocrine disrupting chemicals; EDCs) impacting on reproductive health. We have shown that reproduction in fish (roach, a common member of the carp family of fish) living in many UK Rivers has been damaged by exposure to EDCs contained in the wastewater treatment works (WwTW) effluents and the chemicals responsible for these effects include natural oestrogen hormones and pharmaceutical oestrogens in the contraceptive pill. Feminised roach have a reduced capability to breed under competitive breeding conditions and we have evidence (as yet, unpublished) for reduced breeding population sizes in wild roach living in rivers with a high effluent content. Populations with low numbers of breeding individuals lose genetic variation over multiple generations with a greater risk of extinction. Nevertheless, we find that in some stretches of these rivers with high oestrogenic exposure roach populations appear to be reproductively self-sustaining. Establishing whether fish (here roach) have adapted to oestrogenic contaminants, how they do this (the mechanisms) and the possible fitness costs of these adaptations are essential in understanding resilience (and thus sustainability) of fish populations living in these polluted environments.We will examine whether exposure of roach populations to oestrogenic WwTW effluents over multiple generations has resulted in genetic selection and the impacts of selection on the susceptibility in male fish to develop oestrogen-induced effects associated with negative fitness consequences. We will examine for selection by identifying functionally significant changes in their genetic make up. Specifically we will look for differences in genetic poylmorphisms (so called single nucleotide polymorphisms -SNPs) in (1) specific (candidate) genes that we know are important in oestrogen signalling of reproductive (and other life) processes and (2) by using methods that allow us to scan the whole genome for these genetic alterations (using a technique called RAD-tag genotyping). Adopting these methods we expect to find 'footprints' of selection in fish living in rivers with a high oestrogenic effluent content, which should allow identification of novel adaptive processes and suggest important mechanisms of toxicity or survival in effluent rich environments. Uniquely, we are able to do this work because we have in depth knowledge (15 years of study) of the wild populations of roach in the selected UK Rivers that we propose to study.We will establish whether roach populations exposed to high levels of oestrogenic effluent over many generations have adapted to become less responsive to environmental oestrogens and thus are now less susceptible to their associated adverse effects by comparing responses to a controlled exposure to the contraceptive oestrogen, ethinyloestradiol. We will use roach collected from the same clean and WwTW effluent contaminated sites as for the population genetic analyses described above and fish will be exposed for a period of 1 year and effects quantified on responses that have negative fitness consequences in male fish, including ovotestis. This work is intended to greatly improve understanding of the ability of fish to adapt to exposure to environmental pollutants (here oestrogen) and how they do so, in turn helping to inform on fish population resilience in UK rivers receiving WwTW effluent discharges. The work will have importance in the regulation of discharges for the better protection of our aquatic resources and biodiversity and is of very wide interest to the government regulatory bodies, environment protection groups, industry and the wider public.