Patterns and mechanisms of high-elevation adaptation in reptiles and amphibians

爬行动物和两栖动物高海拔适应的模式和机制

• 批准号: RGPIN-2015-06657
• 负责人: Fu, Jinzhong
• 金额: $ 1.89万
• 依托单位: University of Guelph
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=681616
• 关键词: Patterns; mechanisms; elevation; adaptation; reptiles

My research focuses on understanding patterns of the adaptation process and its genetic basis. High-elevation adaptation provides an excellent study system, because it involves multiple stressors (e,g, low oxygen, low temperature, and high UV) and a intertwined genetic basis. We will study high-elevation adaptation of Tibetan reptiles and amphibians using genomic data. 1) Lizards of Phrynocephalus vlangalii live at Tibetan region across a large elevational gradient (2000-4600m). We will sequence its genome and re-sequence 30 individuals from various elevations. Using population genetic analyses (e.g. Fst outlier analysis), we will identify genes and chromosome regions that have experienced positive selection. The functions of these genes and their potential interactions within the genetic network will be analysed. Furthermore, a reciprocal transplant experiment will be conducted. Lizards from a low and a high elevation site will be captured and transplanted. After one month of acclimation, total mRNA will be collected and digital gene expression profiles will be examined. Genes with different expression profiles will be identified. Similarly, their functions and potential interactions will be analysed. 2) Our previous genomic works on a common toad, Bufo gargarizans, have revealed several important patterns, and one of them is a strong convergent evolution of the MYBPC2 gene, which involves heart muscle contractility. We hypothesized that modifications of cardiac function play a key role in high-elevation adaptation of amphibians and predict that MYBPC2 genes of other high-elevation amphibian species share a similar convergent pattern. We will sequence this gene from at least ten other high-elevation amphibians and test our hypothesis. We will also identify key mutations within this gene along high-elevation lineages. 3) Mitochondrial genome and its co-adaptive evolution with the nuclear genome likely play a key role in thermal adaptation. Two brown frogs, Rana chensiensis (low elevations) and R. kukunoris (high elevations), hybridize across a wide range of elevations and exhibit elevation-specific dynamics. Different combinations of mitochondrial and nuclear genomes between the two species exist in natural populations. We will sequence genes from both genomes that code for the electron transport chain. We will also measure the metabolic rates of hybrid individuals with various genome combinations, as well as rates of mitochondria themselves. Reptiles and amphibians are probably better model systems for studying high-elevation adaptation and early works have revealed a more complex genetic basis, compared to mammals and birds. Poikilotherms represent the majority of animal diversity, and our work will generate widely applicable hypotheses and provide insights into the adaptation process and its genetic basis.

我的研究重点是了解适应过程的模式及其遗传基础。高海拔适应提供了一个很好的研究系统，因为它涉及多种应激源（例如，低氧，低温和高紫外线）和交织的遗传基础。我们将利用基因组数据研究西藏爬行动物和两栖动物的高海拔适应。1)青海沙蜥（Phrynocephalusvlangalii）分布于海拔2000- 4600 m的青藏高原。我们将对它的基因组进行测序，并对来自不同海拔地区的30个个体进行重新测序。使用群体遗传分析（例如Fst离群值分析），我们将识别经历了正选择的基因和染色体区域。将分析这些基因的功能及其在遗传网络中的潜在相互作用。此外，还将进行相互移植实验。将从低海拔和高海拔地区采集并移植落叶松。驯化一个月后，收集总mRNA并检查数字基因表达谱。将鉴定具有不同表达谱的基因。同样，将分析它们的职能和潜在的相互作用。2)我们之前对一种常见的蟾蜍（Bufo gargarizans）的基因组研究揭示了几种重要的模式，其中之一是MYBPC 2基因的强烈趋同进化，该基因涉及心肌收缩性。我们假设心脏功能的改变在两栖动物的高海拔适应中起着关键作用，并预测其他高海拔两栖动物物种的MYBPC 2基因具有类似的收敛模式。我们将从至少10种其他高海拔两栖动物中测序这个基因，并验证我们的假设。我们还将确定沿沿着高海拔血统在这个基因内的关键突变。3)线粒体基因组及其与核基因组的共适应进化可能在热适应中起关键作用。两种棕色蛙，中国林蛙（Rana chensiensis）（低海拔）和中国林蛙（R. kukunoris（高海拔），在很大的海拔范围内杂交，并表现出特定的海拔动态。两个物种之间的线粒体和核基因组的不同组合存在于自然群体中。我们将对两个基因组中编码电子传递链的基因进行测序。我们还将测量具有各种基因组组合的杂交个体的代谢率，以及线粒体本身的代谢率。爬行动物和两栖动物可能是研究高海拔适应性的更好的模型系统，与哺乳动物和鸟类相比，早期的工作揭示了更复杂的遗传基础。Poikilotherms代表了大多数动物的多样性，我们的工作将产生广泛适用的假设，并提供深入了解适应过程及其遗传基础。