Temperature sensitive male fertility; uncovering the mechanisms that make fertility in some species more vulnerable to high temperature

温度敏感的男性生育能力；

基本信息

批准号：
BB/W016753/1
负责人：
Amanda Bretman
金额：
$ 82.35万
依托单位：
University of Leeds
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2023
资助国家：
英国
起止时间：
2023 至无数据
项目状态：
未结题

来源：
https://gtr.ukri.org/projects?ref=BB%2FW016753%2F1
关键词：
Temperature sensitive male fertility uncovering

项目摘要

The climate is warming, and this is predicted to result in an increase in extremes of temperature. Understanding how this will affect the survival and distribution of organisms is vital if we are to prevent extinctions, and invasions by harmful pests. The impacts of climate change are often estimated by examining the temperatures that kill animals. However, we may be underestimating the impact that non-lethal high temperatures have on organisms. In most animals, from beetles to birds to badgers, males typically lose their fertility at a far lower temperature than that required to kill them. This also affects livestock, so that breeds which do well in temperate countries can be infertile in the tropics. Even humans, despite being able to control temperatures using clothes, houses, and air conditioning, show evidence of reductions in fertility during heatwaves. If increasing temperatures cause all the males in an animal population to become sterile, then that population will not survive, even if the temperatures are nowhere near high enough to actually kill any animals. Recently we systematically tested the impact of temperature on the fertility of 43 species of fruit fly. In more than half, males lost fertility at a much cooler temperatures than their lethal limits. We then looked at where the flies were found worldwide. We found that across species and habitats, the highest temperature a species experiences in nature was far better predicted by sterilising temperature limits than by lethal temperature limits. This strongly suggests that temperature-induced sterility really does matter in nature, and that distributions of many species are limited by their ability to remain fertile at high temperatures. If so, then we are likely underestimating the impact of climate change on species, because we are only now realising that losses of fertility may be a major problem.However, very little is known about the physiological and genetic processes which mean species are differently sensitive to temperature-based infertility. For example, whilst it has long been known that Heat Shock Proteins are critical to protecting cells from high temperatures in terms of survival, we don't yet know if the same proteins protect sperm. Our previous work shows that heat-shock might not affect existing mature sperm, but when these are used, species become infertile and don't seem to be able to recover. This suggests that it is the process of making sperm (spermatogenesis) that is damaged by heat.We will study 7 species of fruit fly, which cover the range both in absolute differences in temperature tolerance, and the difference between the limits of fertility and survival. We will assess when spermatogenesis breaks down, using microscope images to describe if heat damages the sperm morphology or the DNA packaged inside. To understand which genes are important, we will measure gene expression in testes both before and after heat shock, to assess if some species are primed to respond more quickly. Crucially, we will not just correlate these findings, but use genetic and chemical manipulations to directly test the function of specific genes. Once we know what causes variation between these fly species, this can then be tested across other animals. Ultimately, this information could be used to quickly assess which species will be vulnerable to high temperature and identify particular genes to target in livestock breeding, to generate more thermally robust breeds.

气候正在变暖，预计这会导致温度极端的升高。如果我们要防止灭绝并因有害害虫的入侵，了解这将如何影响生物的生存和分布至关重要。气候变化的影响通常是通过检查杀死动物的温度来估计的。但是，我们可能低估了非致命的高温对生物的影响。在大多数动物中，从甲虫到鸟类再到badge，雄性通常在温度低得多的温度下失去生育能力。这也会影响牲畜，因此在温带国家中表现良好的繁殖在热带地区可能是不育的。即使人类能够使用衣服，房屋和空调来控制温度，但仍显示出热浪中生育能力降低的证据。如果温度升高会导致动物种群中的所有雄性变得无菌，那么即使温度远不及实际杀死任何动物，该人群也无法生存。最近，我们系统地测试了温度对43种果蝇生育能力的影响。在超过一半的情况下，男性在凉爽的温度下失去了生育能力，而不是致命的极限。然后，我们查看了全世界发现苍蝇的位置。我们发现，在物种和栖息地中，Anative温度限制的最高温度比通过致命的温度限制更好地预测了。这强烈表明，温度引起的无菌性确实在本质上确实很重要，并且许多物种的分布受到其在高温下保持肥沃的能力的限制。如果是这样，那么我们可能会低估气候变化对物种的影响，因为我们现在才意识到生育能力的损失可能是一个主要问题。基于温度的不育。例如，尽管长期以来一直知道热休克蛋白对于保护细胞在生存方面免受高温的影响至关重要，但我们尚不知道同一蛋白是否保护精子。我们以前的工作表明，热震可能不会影响现有的成熟精子，但是当使用这些精子时，物种会变得不育并且似乎无法恢复。这表明正是使精子（精子发生）受热的过程。我们将研究7种果蝇物种，它们涵盖了温度耐受性绝对差异的范围，以及生育率和生存范围之间的差异。我们将使用显微镜图像来评估何时分解精子发生，以描述热量是否损害了精子形态或包装内部包装的DNA。为了了解哪些基因很重要，我们将在热冲击前后测量睾丸中的基因表达，以评估某些物种是否被启动以更快地反应。至关重要的是，我们不仅将这些发现相关联，而且使用遗传和化学操作直接测试特定基因的功能。一旦我们知道是什么原因导致这些蝇物种之间的变化，就可以对其他动物进行测试。最终，这些信息可用于快速评估哪些物种容易受到高温的影响，并确定特定的基因以靶向牲畜育种，以产生更热的良好品种。