PRF/J: Mechanisms of Speciation in an African Rift Lake and the Relationship Between Morphological Divergence and Molecular Variation

四种前鳃腹足类线粒体DNA序列分析 属（Lavigeria，Limnotrochus，Reymondia，Cleopatra）将被使用 来检验爆炸性物种形成对 变化量 这解决了目前关于这个问题的争论 分支发生是否会加快分子进化的速度。 根据这些数据，将使用一个（待构建的）遗传学来测试 两种竞争性的异地物种形成假说 已经被提出来解释地方病的极端多样性， 东非坦噶尼喀湖的动物群。 一种假设是 将湖泊分隔成不同的盆地， 认为现有的栖息地差异足以驱动 物种形成 高度多样性的两个基因的序列差异 特有分支，它的非多样性姐妹群，一个相关的同域群， 属，和一个河流外群。 结果将显示：（a）如何 形态和分子差异与相对 年龄的分支，和（B）是否形态和分子 分歧是相关的不同分支内。 另一个目标 是比较线粒体序列变异的模式， 不同的腹足类分支与那些来自不同的同域慈鲷 鱼类，以得出一个一般的湖泊物种形成模式， 确定保护优先事项。 %%% 获得的分子数据集将用于测试 从以前的形态测量中得出的系统发育结论 贝壳、软体解剖和电泳特征的研究。 这些软体动物并不特别了解， 物种数量，生活史和生态学，因此这项研究将 提供学习基础生物学细节的机会。 过去对坦噶尼喀湖的研究主要集中在慈鲷和 预期的研究承诺会产生一种比较的“尺度”， 将这些调查置于更广泛的背景下进行。 在 此外，这将是第一个分子遗传学研究， 坦噶尼喀水生无脊椎动物，尽管它们是主要的 底栖生态系统的组成部分。

Mitochondrial DNA sequences from four prosobranch gastropod genera (Lavigeria, Limnotrochus, Reymondia, Cleopatra) will be used to examine the effect of explosive speciation on molecular variation. This addresses a current controversy over the question of whether cladogenesis increases the rate of molecular evolution. From this data a phylogeny (to be constructed) will be used to test two competing hypotheses of allopatric speciation; the hypotheses have been proposed to explain the extreme diversity of endemic fauna in Lake Tanganyika, East Africa. One hypothesis relies on separation of the lake into distinct basins while the other maintains that existing habitat differences are sufficient to drive speciation. Sequence divergence from two genes of a highly diverse endemic clade, its nondiverse sister group, a related sympatric genus, and a fluvial outgroup. Results will show: (a) how morphological and molecular divergence are correlated with relative ages of the clades, and (b) whether morphological and molecular divergence are correlated within the diverse clade. Another goal is to compare patterns of mitochondrial sequence variation in the diverse gastropod clade with those from a diverse sympatric cichlid fish to derive a general lacustrine speciation model and to identify conservation priorities. %%% The molecular data set to be obtained will be used to test phylogenetic conclusions that emerged from previous morphometric studies of shell, soft anatomy, and electrophoretic characters. These molluscs are not particularly well known with regard to number of species, life histories, and ecology, so this study will provide the opportunity to learn details of fundamental biology. Past studies of Lake Tanganyika focussed on cichlid fish and the intended studies promise to yield a sort of comparative "yardstick" for those investigations by placing them in a broader context. In addition this will be the first molecular genetic study of Tanganyikan aquatic invertebrates, despite the fact they are major components of the benthic ecosystem.