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

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(如低氧、低温和高紫外线)和相互交织的遗传基础。我们将利用基因组数据研究藏族爬行动物和两栖动物的高海拔适应。1)大海拔梯度(2000-4600米)的藏区有沙棘蜥蜴。我们将对它的基因组进行排序，并对来自不同海拔的30个个体进行重新排序。利用群体遗传学分析(例如Fst离群值分析)，我们将识别经历过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。来自低海拔和高海拔地点的蜥蜴将被捕获并移植。驯化一个月后，将收集总mRNA，并检查数字基因表达谱。具有不同表达谱的基因将被识别出来。同样，将分析它们的功能和潜在的相互作用。2)我们以前对一种常见的蟾蜍(Bufo Gargarizans)的基因组工作揭示了几种重要的模式，其中之一是MYBPC2基因的强烈收敛进化，它涉及到心肌收缩。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的MYBPC2基因具有类似的收敛模式。我们将对至少10种其他高海拔两栖动物的这个基因进行测序，并验证我们的假设。我们还将沿着高海拔血统确定该基因内的关键突变。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(低海拔)和库库诺里斯蛙(高海拔)，在广泛的海拔范围内杂交，并表现出特定于海拔的动态。这两个物种之间线粒体和核基因组的不同组合存在于自然种群中。我们将对两个基因组中编码电子传输链的基因进行测序。我们还将测量具有不同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的更好的模型系统，早期的工作揭示了比哺乳动物和鸟类更复杂的遗传基础。泊卡温度代表了大多数动物多样性，我们的工作将产生广泛适用的假说，并为适应过程及其遗传基础提供见解。

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.