Collaborative Research: SG: Genomic and functional tests of mitochondrial-nuclear coevolution

合作研究：SG：线粒体-核协同进化的基因组和功能测试

• 批准号: 1753695
• 负责人: Kristi Montooth
• 金额: $ 9万
• 依托单位: University of Nebraska-Lincoln
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-07-01 至 2022-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1753695&HistoricalAwards=false
• 关键词: Collaborative; Research; SG; Genomic; functional

Harmful mutations can negatively affect gene, protein, and organism function. In the extreme, the accumulation of harmful mutations can lead to population extinction. The genetic information in mitochondria - the main source of energy production in most complex organisms - is usually passed intact from parents to offspring. Thus, the mitochondria should be especially prone to the buildup of harmful mutations. However, mitochondria have maintained their function for more than one billion years; how and why is an important question in evolutionary biology. This research uses a model snail system to address these questions. It takes advantage of the fact that some lineages of snails pass both their nuclear and mitochondrial genomes on to their offspring without any genetic shuffling; a process that accelerates the accumulation of mutations in these snails. By contrast, there is shuffling of genetic material between parents and offspring in other lineages of the same snail species. This project will compare different lineages of snails, some with genetic shuffling and some without. In doing so, this research will explore how harmful mutations are cleared from populations. Reducing the impact of harmful mutations is important for keeping organisms healthy. In turn, healthy organisms can guard against population extinction. It is possible that harmful mutations in the mitochondria are compensated for by mutations in nuclear genes. This hypothesis will also be tested by this research. Because functional mitochondria are important to the health of many organisms, the research will be relevant to the biomedical and agricultural communities. The research will also train a new generation of scientists and broaden participation in biology. The broader impacts include collaborations with high school students and museums. The project will also extend an award-winning partnership with the National Center for Science Education to new audiences.The research combines genetic and functional methods to test for signatures of mitochondrial-nuclear coevolution in the New Zealand freshwater snail Potamopyrgus antipodarum. In this snail system, some lineages are sexual and others are asexual. Crucially for this study, the asexual lineages of P. antipodarum have higher mitochondrial substitution rates than the sexual lineages. This contrast in mitochondrial substitution rates permits the study's two objectives. Objective 1 will test the hypothesis that higher mitochondrial substitution rates in asexual versus sexual lineages drive stronger mitochondrial-nuclear molecular coevolutionary dynamics. One prediction of these coevolutionary dynamics is that substitution rates for proteins encoded by the nuclear genome that are then targeted to the mitochondria will be higher than the substitution rates in control nuclear gene sets. Objective 2 will test for functional effects of mitonuclear interactions on mitochondrial respiration and snail metabolic rate. Since temperature can impact snail metabolic rates, the second objective will include four different temperature treatments. Results of this research will contribute to our understanding of the mitochondrial-nuclear interactions that define eukaryotes. Furthermore, they are of broad relevance to genome evolution, speciation, and the functional and evolutionary consequences of reproductive mode variation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

有害突变会对基因，蛋白质和生物体功能产生负面影响。在极端情况下，有害突变的积累会导致人口灭绝。线粒体中的遗传信息 - 大多数复杂生物的主要能源生产来源 - 通常是从父母到后代完整的。因此，线粒体应该特别容易构成有害突变。但是，线粒体维持其功能超过十亿年。进化生物学中的重要问题以及为什么是一个重要的问题。该研究使用模型蜗牛系统来解决这些问题。它利用了这样一个事实，那就是蜗牛的一些谱系将其核和线粒体基因组传递到其后代，而没有任何遗传改组。一个加速这些蜗牛突变积累的过程。相比之下，在同一蜗牛物种的其他谱系中，父母和后代之间存在遗传物质。该项目将比较蜗牛的不同谱系，有些则具有遗传改组，有些则没有。通过这样做，这项研究将探讨如何从人群中清除有害突变。减少有害突变的影响对于保持生物体健康很重要。反过来，健康的生物可以防止人口灭绝。线粒体中有害突变可能被核基因中的突变弥补。该研究也将通过这项研究来检验。由于功能性线粒体对许多生物的健康很重要，因此该研究将与生物医学和农业社区有关。该研究还将培训新一代的科学家，并扩大对生物学的参与。更广泛的影响包括与高中生和博物馆的合作。该项目还将将与国家科学教育中心的屡获殊荣的合作伙伴扩展到新的受众。该研究结合了遗传和功能方法，以测试新西兰淡水淡水Snail Snail Potamopyrgus Antipodarum的线粒体核核协同进化的特征。在这个蜗牛系统中，有些谱系是性的，而另一些是无性恋的。至关重要的是，对于这项研究而言，抗二疟原虫的无性谱系具有比性谱系高的线粒体取代率更高。线粒体取代率的这种对比允许研究的两个目标。目标1将检验以下假设：无性谱系中较高的线粒体取代率促进了更强的线粒体 - 核分子共同进化动力学。这些协同进化动态的一种预测是，核基因组编码的蛋白质的替代速率随后被靶向线粒体的蛋白质将高于控制核基因集中的替代速率。目标2将测试线核相互作用对线粒体呼吸和蜗牛代谢率的功能作用。由于温度会影响蜗牛代谢率，因此第二个目标将包括四种不同的温度处理。这项研究的结果将有助于我们理解定义真核生物的线粒体核相互作用。此外，它们与基因组进化，物种形成以及生殖模式变化的功能和进化后果具有广泛的相关性。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响的审查标准来评估的。