Dissertation Research: An Experimental and Genetic Analysis of Two Salamander Contact Zones: Adaptive, Biogeographic, and Systematic Implications

论文研究：两个蝾螈接触区的实验和遗传分析：适应性、生物地理和系统意义

• 批准号: 0072869
• 负责人: David Wake
• 金额: $ 1万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-06-15 至 2003-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0072869&HistoricalAwards=false
• 关键词: Dissertation; Research; Experimental; Genetic; Analysis

0072869Wake and KuchtaContact zones, where biological lineages once geographically separated come back together, are windows to the evolutionary process that enable the study of diverse evolutionary phenomena. Graduate student Shawn Kuchta, under the direction of Dr. David Wake, will use molecular techniques and field experiments to study two cryptic contact zones in two unrelated salamander taxa. In the Ensatina eschscholtzii (Caudata: Plethodontidae) complex, two distinct subspecies (oregonensis and xanthoptica) contact in northern California. An earlier detailed analysis of color pattern characterized the interaction as broad intergradation, but new molecular data suggest a tight genetic border. The hypothesis under test is that the "intergradation" of color pattern is introgression across a hybrid zone because the xanthoptica color pattern is a potential mimic of the extremely toxic newts of the genus Taricha. The contact zone between oregonensis and xanthoptica will be characterized genetically using mitochondrial (mt) DNA molecular sequence data, allozymes, and Restriction Fragment Length Polymorphisms (RFLPs) of nuclear DNA. Tests of bird predation will employ clay models in field experiments designed to test the possibility of a mimicry system between xanthoptica and Taricha. The second contact zone is located in the southern Sierra Nevada, where two clades of the California Newt, Taricha torosa, contact. This border is truly cryptic: it appears that T. torosa from the coast ranges colonized the southern Sierra Nevada, then acquired the phenotypic characteristics of Sierra Nevada populations. The causes of this phenotypic shift are unclear. Nuclear and mtDNA markers will be used to characterize the contact zone, and to investigate the cause of the phenotypic evolution of the southern Sierra Nevada populations. Both of these studies are grounded in population-level phylogenetics and an empirical approach to the study of species formation and differentiation.

0072869韦克和库赫塔接触区，曾经在地理上分离的生物谱系重新聚集在一起，是进化过程的窗口，可以研究不同的进化现象。 研究生 Shawn Kuchta 在 David Wake 博士的指导下，将利用分子技术和现场实验来研究两个不相关的蝾螈类群中的两个神秘接触区。 在 Ensatina eschscholtzii（有尾目：Plethodontidae）复合体中，两个不同的亚种（oregonensis 和 xanthoptica）在加利福尼亚州北部接触。 早期对颜色模式的详细分析将相互作用描述为广泛的整合，但新的分子数据表明紧密的遗传边界。 正在测试的假设是，颜色图案的“融合”是跨混合区的渗入，因为 xantoptica 颜色图案是 Taricha 属剧毒蝾螈的潜在模仿者。 将使用线粒体 (mt) DNA 分子序列数据、同种酶和核 DNA 的限制性片段长度多态性 (RFLP) 对俄勒冈州和 xanthoptica 之间的接触区进行遗传学表征。鸟类捕食的测试将在现场实验中使用粘土模型，旨在测试 xanthoptica 和 Taricha 之间拟态系统的可能性。 第二个接触区位于内华达山脉南部，加州蝾螈（Taricha torosa）的两个分支在此接触。 这个边界确实很神秘：看起来来自海岸山脉的托罗萨（T. torosa）定居在内华达山脉南部，然后获得了内华达山脉种群的表型特征。 这种表型转变的原因尚不清楚。核和线粒体DNA标记将用于表征接触区，并调查内华达山脉南部种群表型进化的原因。 这两项研究都基于种群水平的系统发育学和物种形成和分化研究的实证方法。