Salmonid Experimental Station at Campos do Jordão, UPD-CJ (APTA/SAA), Campos do Jordão, Brazil.
Laboratorio de Biología del Desarrollo, Instituto Tecnológico de Chascomús (CONICET-UNSAM), Chascomús, Argentina.
Cell Mol Life Sci. 2020 Nov;77(21):4223-4236. doi: 10.1007/s00018-020-03532-9. Epub 2020 May 4.
The determination of sex is an important hallmark in the life cycle of organisms, in which the fate of gonads and then the individual sex are defined. In gonochoristic teleost fish, this process is characterized by a high plasticity, considering that in spite of genotypic sex many environmental factors can cause shifts from one to another molecular pathway, resulting in organisms with mismatching genotypic and phenotypic sexes. Interestingly, in most instances, both female-to-male or male-to-female sex-reversed individuals develop functional gonads with normal gametogenesis and respective progenies with full viability. The study of these mechanisms is being spread to other non-model species or to those inhabiting more extreme environmental conditions. Although water temperature is an important mechanism involved in sex determination, there are other environmental stressors affected by the climate change which are also implicated in stress response-induced masculinization in fish. In this regard, the brain has emerged as the transducer of the environment input that can influence the gonadal fate. Furthermore, the evaluation of other environmental stressors or their synergic effect on sex determination at conditions that simulate the natural environments is growing gradually. Within such scope, the concerns related to climate change impacts rely on the fact that many of biotic and abiotic parameters reported to affect sex ratios are expected to increase concomitantly as a result of increased greenhouse gas emissions and, particularly worrying, many of them are related to male bias in the populations, such as high temperature, hypoxia, and acidity. These environmental changes can also generate epigenetic changes in sex-related genes affecting their expression, with implications on sex differentiation not only of exposed individuals but also in following generations. The co-analysis of multi-stressors with potential inter- and transgenerational effects is essential to allow researchers to perform long-term predictions on climate change impacts in wild populations and for establishing highly accurate monitoring tools and suitable mitigation strategies.
性别决定是生物生命周期中的一个重要标志，在此过程中，性腺的命运以及个体的性别被确定。在雌雄同体的硬骨鱼中，尽管基因型性别是固定的，但许多环境因素都可能导致从一种分子途径向另一种途径转变，从而产生基因型和表型性别不匹配的个体，这一过程具有高度的可塑性。有趣的是，在大多数情况下，雌性到雄性或雄性到雌性的性反转个体都会发育出具有正常配子发生功能的性腺，并产生具有完全生存能力的相应后代。这些机制的研究正在扩展到其他非模式物种或生活在更极端环境条件下的物种。虽然水温是性别决定的一个重要机制，但气候变化引起的其他环境胁迫因素也会导致鱼类应激反应诱导的雄性化。在这方面，大脑已经成为环境输入的转换器，可以影响性腺的命运。此外，评估其他环境胁迫因素或它们在模拟自然环境条件下对性别决定的协同作用也在逐渐增加。在这种范围内，与气候变化影响相关的担忧依赖于这样一个事实，即许多报道会影响性别比例的生物和非生物参数预计会随着温室气体排放的增加而同时增加，更令人担忧的是，其中许多与种群中的雄性偏倚有关，如高温、缺氧和酸度。这些环境变化还会导致与性别相关的基因发生表观遗传变化，从而影响其表达，不仅对暴露个体的性别分化，而且对后代的性别分化都有影响。对具有潜在的跨代和跨代影响的多胁迫因素进行共同分析，对于研究人员对野生种群中气候变化影响进行长期预测以及建立高度准确的监测工具和合适的缓解策略至关重要。
