Selection experiments and sequencing to identify mechanisms of thermal adaptation in a splash pool copepod

选择实验和测序以确定飞溅池桡足类热适应机制

• 批准号: 2154283
• 负责人: Morgan Kelly
• 金额: $ 130.42万
• 依托单位: Louisiana State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-05-15 至 2025-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2154283&HistoricalAwards=false
• 关键词: Selection; experiments; sequencing; identify; mechanisms

Heat tolerance is an important trait, because it influences where a species can live, and whether it will survive in a warming climate. Heat tolerance varies among species, but little is understood about the genetic differences that make some animals and plants more heat tolerant than others. This research will use the small marine crustacean, Tigriopus californicus, as an experimental model to investigate the genetic changes lead to increased heat tolerance. The researchers will conduct a series of evolution experiments, where they will artificially select for increased heat tolerance in Tigriopus in the laboratory. At the end of the experiments they will sequence the genomes of the experimental populations to examine which genetic changes led to greater heat tolerance. Then they will compare these genetic changes to differences among northern and southern populations of Tigriopus, which naturally differ in their heat tolerance, to test whether the same changes are responsible for increased heat tolerance in the lab and in nature. This research will contribute a greater understanding of why some species are more heat tolerant than others, leading to an improved ability to predict which species will be more vulnerable to climate change. An understanding of the genetic changes that lead to greater heat tolerance could also be used in aquaculture and in conservation breeding programs, to identify which strains of a given species are the most likely to be resilient to warming.Thermal tolerance traits govern the abundance and distribution of organisms across environments and shape organismal responses to climate change. However, mechanisms determining variation in thermal tolerance are poorly understood for most species. The splash pool copepod Tigriopus californicus exhibits divergent thermal tolerance traits across populations, and is easily crossed and reared in the lab. As a result, it is an excellent model for examining mechanisms of temperature adaptation. The researchers will perform three selection experiments, each targeting a different aspect of thermal performance that differs among Tigriopus populations: (A) upper lethal limits, (B) plasticity of thermal limits, and (C) thermal optima. They will combine these experiments with physiological measurements, transcriptome profiling, and whole-genome resequencing to identify mechanisms underlying each aspect of thermal adaptation. Finally, they will compare results of laboratory experiments to population resequencing data for two Tigriopus species distributed over parallel temperature gradients in North and South America. Results of this project will provide a comprehensive map of the genetic and physiological bases of temperature adaptation in this species, and shed light on key questions, including the role of gene regulation vs. protein coding changes in physiological divergence among populations, the proportion of the genome involved in temperature adaptation, the costs and trade-offs imposed by the evolution of increased thermal breadth, and the repeatability of adaptation across parallel environmental gradients.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.

耐热性是一个重要的性状，因为它影响一个物种可以生活的地方，以及它是否能在变暖的气候中生存。不同物种的耐热性各不相同，但人们对使一些动物和植物比其他动物和植物更耐热的遗传差异知之甚少。 本研究将利用小型海洋甲壳动物，Tigriopus californicus作为实验模型，研究导致耐热性增加的遗传变化。 研究人员将进行一系列的进化实验，在实验室中，他们将人工选择增加Tigriopus的耐热性。 在实验结束时，他们将对实验种群的基因组进行测序，以检查哪些遗传变化导致了更大的耐热性。然后，他们将比较这些遗传变化与虎首属北方和南方种群之间的差异，这些种群的耐热性自然不同，以测试相同的变化是否是实验室和自然界中耐热性增加的原因。 这项研究将有助于更好地理解为什么有些物种比其他物种更耐热，从而提高预测哪些物种更容易受到气候变化影响的能力。 对导致更高耐热性的遗传变化的理解也可以用于水产养殖和保护育种计划，以确定给定物种的哪些菌株最有可能适应变暖。耐热性性状决定了生物在环境中的丰度和分布，并塑造了生物对气候变化的反应。然而，大多数物种对决定耐热性变化的机制知之甚少。飞溅池桡足类加州虎足虫（Tigriopus californicus）在不同种群间表现出不同的耐热性，易于在实验室中杂交和饲养。因此，它是研究温度适应机制的一个很好的模型。 研究人员将进行三个选择实验，每个实验针对Tigriopus种群之间不同的热性能的不同方面：（A）致死上限，（B）热极限的可塑性，以及（C）热最佳。 他们将联合收割机这些实验与生理测量，转录组分析和全基因组重测序相结合，以确定热适应的每个方面的机制。最后，他们将比较实验室实验的结果与分布在北美和南美平行温度梯度上的两种虎斑蝶的种群重测序数据。 该项目的结果将提供该物种温度适应的遗传和生理基础的全面地图，并阐明关键问题，包括基因调控与蛋白质编码变化在种群间生理分化中的作用，参与温度适应的基因组比例，增加的热宽度进化所带来的成本和权衡，该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。