Dissertation Research: Linking climate dynamics and historical demographic in South American forest lizards

论文研究：将南美森林蜥蜴的气候动态和历史人口统计联系起来

• 批准号: 1601271
• 负责人: Ana Carnaval
• 金额: $ 1.26万
• 依托单位: CUNY Graduate School University Center
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-06-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1601271&HistoricalAwards=false
• 关键词: Dissertation; Research; Linking; climate; dynamics

Tens of thousands of years ago the levels of rainfall in northeastern South America were much higher than today. As a result, the Amazon and the Atlantic rainforests were much more extensive, occupying regions that are today covered by deserts and savannahs. When the climate became drier, those forests retracted and became fragmented. This change likely had dramatic effects on the animals and plants that live in tropical rainforests. This project asks how tropical forest organisms were affected by the climatic changes experienced over the past 250,000 years. The genomes of three species of lizards that occur in the Brazilian forests will be studied, and by comparing the DNA sequences of multiple individuals per species over their geographic range, the project will uncover the extent that their populations have expanded or declined in the past. This research shed light on how these organisms have responded to environmental change, in addition to the processes that led to their current distribution patterns. This project will provide training in molecular systematic methods and mentorship for undergraduate and Masters students at The City College of New York. It also will foster new USA-Brazil scientific collaborations through joint field trips to northern Brazil.This project seeks to test how populations of forest-associated lizards have been affected by a recently proposed dynamics of moisture transport in South America during the Quaternary. It will generate Single Nucleotide Polymorphism (SNP) data of three arboreal lizard species that occur in both Amazon and the Atlantic rainforests (Anolis punctatus, A. ortonii and Polychrus marmoratus) using a restriction-site associated DNA sequencing protocol. Phylogenetic relationships will be inferred using coalescent-based methods. Analyses of genetic structure will be performed to infer the number of effective populations within the different species. Scenarios of population expansion, contraction, or persistence will be evaluated based on coalescent simulations and both likelihood-based methods and Approximate Bayesian Computation. Estimates of demographic parameters such as effective population sizes, divergence times between populations, and migration rates will be estimated using best-fit models. Together these data will provide new insights on the population structure for taxa in the Brazilian Atlantic and Amazonian rainforests, and how they have responded to recent climate perturbations.

数万年前，南美东北部的降雨量远高于今天。结果，亚马逊和大西洋雨林更为广泛，如今已被沙漠和萨凡纳人覆盖。当气候变得更干燥时，这些森林缩回并变成了分散。这种变化可能对生活在热带雨林中的动物和植物产生了巨大影响。该项目询问热带森林生物如何受到过去25万年中气候变化的影响。将研究在巴西森林中发生的三种蜥蜴的基因组，并通过比较每个物种在其地理范围内的多个个体的DNA序列，该项目将揭示其种群在过去扩展或下降的程度。这项研究揭示了这些生物对环境变化的反应，除了导致当前分布模式的过程外。该项目将为纽约市城市学院的本科生和硕士学生提供分子系统方法和指导的培训。 它还将通过前往巴西北部的联合实地考察来促进新的美国 - 巴西科学合作。该项目旨在测试Quaternary期间南美洲最近提出的水分运输动力学的森林相关蜥蜴人群。它将生成三种树木蜥蜴物种的单核苷酸多态性（SNP）数据，这些蜥蜴物种都使用限制性site-site相关的DNA测序方案在亚马逊和大西洋雨林（Anolis punctatus，A。ortonii和polychrus marmoratus）中产生。系统发育关系将使用基于合结的方法推断。将对遗传结构进行分析，以推断不同物种内有效人群的数量。人口扩展，收缩或持久性的场景将根据共聚的模拟以及基于似然的方法和近似贝叶斯计算进行评估。人口参数的估计值，例如有效的人口规模，人群之间的差异时间以及迁移率将使用最佳拟合模型估算。这些数据将共同提供有关巴西大西洋和​​亚马逊雨林中分类单元的人口结构的新见解，以及它们如何应对最近的气候扰动。