Causations of a riverine radiation: Assessment and evaluation of the morphological and genetical differentiation in a species flock of viviparous gastropods (Cerithioidea: Pachychilidae)

河流辐射的原因：胎生腹足动物群形态和遗传分化的评估和评价（Cerithioidea：Pachychilidae）

• 批准号: 20497935
• 负责人: Dr. Frank Köhler
• 金额: --
• 依托单位: Australian Museum
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2011-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/20497935?language=en
• 关键词: Causations; riverine; radiation; Assessment; evaluation

Species flocks in lakes have frequently been examined as model systems in an attempt to elucidate the underlying evolutionary mechanisms of adaptive radiations. In contrast, riverine radiations are rare and hardly studied. However, due to specific characteristics a riverine setting provides a new perspective for studying potential factors of speciation and, thus, the genesis of biological diversity. The proposed project focuses on an endemic, morphologically diverse species flock of viviparous freshwater gastropods of the genus Brotia inhabiting the Kaek River (Chao Praya drainage, Central Thailand). Preliminary results indicate the Mekong drainage system as a putative area of origin, the monophyly of the species flock, and its rapid diversification. Sympatric occurrence of two to three species at sampling localities, their ecological separation by varying substrate preferences, and a correlated trophic specialization (radula morphology) renders this fluviatile radiation a new and potentially highly informative model system. This project combines sophisticated sampling of material and ecological data in the field with morphological and molecular genetic analyses. We ill employing AFLP genotyping as powerful tool to produce well-resolved phylogenetic reconstructions and to assess levels of genetic variation and cohesion (estimation of gene flow within and between populations) to illuminate the role of intrinsic and extrinsic factors in the course of allopatric and/or ecological speciation. This will be supplemented by data on environment-phenotype correlation and life-history parameters (brood size and performance as estimator for fitness) that is necessary to test assumptions on the causations of the evolution of this species flock.

湖泊中的物种群经常被作为模型系统进行检查，试图阐明适应性辐射的潜在进化机制。相比之下，河流辐射很少见，而且很少被研究。然而，由于河流的具体特征，河流环境为研究物种形成的潜在因素以及生物多样性的起源提供了新的视角。拟议项目的重点是栖息在Kaek河（泰国中部Chao Praya流域）的Brotia属地方性、形态多样的胎生淡水腹足动物群。初步结果表明湄公河排水系统是假定的起源区域，物种群的单一性及其快速多样化。在采样地点同域出现两到三个物种，通过不同的底物偏好进行生态分离，以及相关的营养特化（齿舌形态）使这种河流辐射成为一个新的、潜在的信息丰富的模型系统。该项目将现场材料和生态数据的复杂采样与形态学和分子遗传分析结合起来。我们将使用 AFLP 基因分型作为强大的工具来进行良好解析的系统发育重建，并评估遗传变异和凝聚力的水平（估计种群内部和种群之间的基因流），以阐明内在和外在因素在异域和/或生态物种形成过程中的作用。这将得到有关环境表型相关性和生活史参数（巢体大小和作为适应性估计量的性能）的数据的补充，这些数据对于测试对该物种群体进化的原因的假设是必要的。