US-Tanzania Dissertation Enhancement: Diversification in Lake Tanganyika Endemics: Gastropods and Cichlid Fishes Compared

美国-坦桑尼亚论文增强：坦噶尼喀湖特有物种的多样化：腹足类动物和慈鲷鱼的比较

• 批准号: 0724247
• 负责人: Amy McCune
• 金额: $ 1.9万
• 依托单位: Cornell Univ - State: AWDS MADE PRIOR MAY 2010
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-01 至 2010-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0724247&HistoricalAwards=false
• 关键词: US; Tanzania; Dissertation; Enhancement; Diversification

Since their discovery, the cichlid fish faunas of the East African rift lakes have drawn attention as remarkable cases of within-lake speciation and adaptive divergence. Among these lakes, however, Lake Tanganyika is distinctive in the extent to which its other taxa have also diversified: over 350 unique non-cichlid species are found within this lake. Tanganyika is therefore a unique ecosystem for studying processes of endemic diversification: how is it that some taxa have diversified so dramatically within this single lake? One hypothesis is that substrate heterogeneity in the littoral zone allows taxa to ecologically specialize on specific substrates, and isolation between subpopulations in this heterogeneous environment creates the potential for speciation. Although this hypothesis for within-lake allopatric speciation was first proposed over 25 years ago, its role in creating patterns of species diversity within the East African rift lakes remains largely untested. If isolation of populations through substrate specificity and limited dispersal among habitat patches has driven diversification, it is hypothesized that species from groups with high endemic diversity will show evidence of restricted gene flow between populations. This research will investigate this hypothesis in two unrelated groups that have produced substantial endemic radiations in Lake Tanganyika: Lavigeria gastropods, and cichlid fishes of the tribe Tropheini. Study species of cichlid fishes and snails are all benthic herbivores restricted to rocky substrates. This obligate habitat association, coupled with their notably high lake-wide species diversity, suggests that ecological specialization on rocky substrate has promoted speciation in both snail and cichlid groups. Therefore, ecological specialization may drive parallel genetic subdivision of populations and diversification in multiple unrelated taxonomic groups. To test these hypotheses, both mitochondrial DNA sequence and microsatellite data will be used to analyze comparative patterns of population genetic structuring in cichlids and snails along the heterogeneous shoreline bordering Kigoma, Tanzania. Understanding the impact that ecological specialization has on gene flow dynamics and patterns of diversity across these taxa will allow the testing of important, long-standing questions about the processes of diversification among Lake Tanganyika's exceptionally diverse faunas.

自发现以来，东非裂谷湖的慈鲷鱼动物群作为湖内物种形成和适应性分化的显着案例引起了人们的注意。然而，在这些湖泊中，坦噶尼喀湖在其他类群也多样化的程度上是独特的：在这个湖中发现了350多个独特的非慈鲷物种。因此，坦噶尼喀是一个独特的生态系统，研究过程中的地方性多样化：它是如何在这个单一的湖泊，一些类群多样化如此显着？一种假设是，在沿岸的带的基板异质性允许类群生态专门化特定的基板，在这种异质性环境中的亚群之间的隔离创造了物种形成的潜力。虽然这一假设内湖异域物种形成的首次提出超过25年前，其在东非裂谷湖泊内创造的物种多样性模式的作用仍然在很大程度上未经检验。如果隔离的人群，通过基板特异性和有限的分散在栖息地补丁驱动多样化，据推测，物种从群体具有高地方性的多样性将显示出限制种群之间的基因流的证据。这项研究将调查这一假设在两个不相关的群体，产生了大量的地方性辐射在坦噶尼喀湖：Lavigeria腹足类，和慈鲷科鱼类的部落Tropheini。慈鲷鱼和蜗牛的研究物种都是底栖食草动物，仅限于岩石基板。这种专性的栖息地协会，再加上他们的显着高湖泊范围内的物种多样性，表明生态专业化的岩石基板上，促进了蜗牛和慈鲷类的物种形成。因此，生态专业化可能会推动平行的遗传细分的人口和多样化，在多个不相关的分类群体。为了验证这些假设，线粒体DNA序列和微卫星数据将被用来分析比较模式的慈鲷和蜗牛的种群遗传结构沿着异质海岸线接壤基戈马，坦桑尼亚。了解生态专业化的影响，基因流的动态和模式的多样性在这些类群将允许测试重要的，长期存在的问题，坦噶尼喀湖的异常多样化的动物群之间的多样化的过程。