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 Wake和Kuchtacontact区域曾经在地理上分离的生物谱系又回到一起，是进化过程的窗户，能够研究各种进化现象。 研究生Shawn Kuchta在David Wake博士的指导下，将使用分子技术和现场实验来研究两个无关的Salamander分类群中的两个隐秘接触区。 在北加州的Ensatina Eschscholzii（Caudata：Plethodontidae）复合体中，两个不同的亚种（俄勒冈州和Xanthoptica）接触。 对颜色模式的较早详细分析将相互作用表征为宽分布，但是新的分子数据表明遗传边界紧密。 正在检验的假设是，颜色模式的“互动”是在混合区域内的渗入，因为xanthoptica颜色模式是塔里希属极具毒性的纽约人的潜在模仿。 使用线粒体（MT）DNA分子序列数据，同酶和限制性片段长度多态性（RFLPS），将在遗传上对俄勒冈州和Xanthoptica之间的接触区进行遗传表征。鸟类捕食的测试将在旨在测试Xanthoptica和Taricha之间模仿系统的可能性中采用粘土模型。 第二个接触区位于内华达山脉南部，加利福尼亚纽特的两个进化枝塔里希·托罗萨（Taricha Torosa）接触。 这个边界确实是神秘的：似乎海岸的T. Torosa殖民了内华达山脉南部，然后获得了内华达山脉人口的表型特征。 这种表型转移的原因尚不清楚。核和mtDNA标记将用于表征接触区，并研究内华达山脉南部人口的表型进化的原因。 这两项研究都基于种群水平的系统发育学和对物种形成和分化的研究的经验方法。