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

PRF/J：非洲裂湖的物种形成机制以及形态分化与分子变异之间的关系

• 批准号: 9303281
• 负责人: Alice Michel
• 金额: --
• 依托单位: Individual Award
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-12-01 至 1997-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9303281&HistoricalAwards=false
• 关键词: PRF; Mechanisms; Speciation; African; Rift

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.

将使用来自四个Prosobranch腹足动物属（Lavigeria，Limnotrochus，Reymondia，Cleopatra）的线粒体DNA序列来检查爆炸性物种对分子变异的影响。 这就解决了当前关于锁骨发生是否增加分子进化率的问题的争议。 从这些数据中，系统发育（待构建）将用于检验两个竞争性种种形成的竞争假设。有人提出了假设来解释东非坦any尼卡湖流行动物群的极端多样性。 一个假设依赖于将湖泊分离为不同的盆地，而另一个假设认为现有的栖息地差异足以推动物种形成。 序列差异与高度多样的特有进化枝的两个基因，其非姐妹组，一个相关的同胞属和河流外群。 结果将显示：（a）形态学和分子差异与进化枝的相对年龄如何相关，以及（b）形态学和分子差异是否在各种进化枝内相关。 另一个目标是将各种腹足动物进化枝中线粒体序列变化的模式与来自多种同伴丽鱼科鱼类鱼类的那些形成的模式，以得出一般的湖泊形成模型并识别保护优先级。 %% %%将使用要获得的分子数据集来测试从先前对壳，软解剖和电泳特征的形态学研究中得出的系统发育结论。 这些软体动物在物种，生命史和生态学方面并不是特别众所周知，因此本研究将为学习基本生物学的细节提供机会。 过去对坦any尼湖的研究集中在丽鱼科鱼类上，预期的研究有望通过将它们放置在更广泛的背景下，为这些调查产生一种比较的“标准”。 此外，尽管事实是底栖生态系统的主要组成部分，但这将是Tanganyikan水生无脊椎动物的第一个分子遗传研究。