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，南美洲东北部的降雨量比今天高得多。结果，亚马逊和大西洋雨林变得更加广阔，占据了今天被沙漠和稀树草原覆盖的地区。当气候变得干燥时，这些森林就会萎缩并变得支离破碎。这种变化可能对生活在热带雨林中的动植物产生巨大影响。该项目探讨过去 25 万年的气候变化如何影响热带森林生物。该项目将研究巴西森林中三种蜥蜴的基因组，并通过比较其地理范围内每个物种的多个个体的 DNA 序列，揭示其种群在过去扩大或减少的程度。这项研究揭示了这些生物体如何应对环境变化，以及导致其当前分布模式的过程。该项目将为纽约城市学院的本科生和硕士生提供分子系统方法培训和指导。 它还将通过对巴西北部的联合实地考察促进新的美国-巴西科学合作。该项目旨在测试最近提出的第四纪期间南美洲水分输送动态如何影响与森林相关的蜥蜴种群。它将使用限制位点相关 DNA 测序方案生成亚马逊和大西洋雨林中三种树栖蜥蜴物种（Anolis punctatus、A. ortonii 和 Polychrus marmoratus）的单核苷酸多态性 (SNP) 数据。将使用基于合并的方法推断系统发育关系。将进行遗传结构分析以推断不同物种内有效种群的数量。人口扩张、收缩或持续的情景将根据合并模拟以及基于可能性的方法和近似贝叶斯计算进行评估。将使用最佳拟合模型来估计人口参数，例如有效人口规模、人口之间的分歧时间和迁移率。这些数据将为巴西大西洋和​​亚马逊雨林的类群种群结构以及它们如何应对最近的气候扰动提供新的见解。