Marine Biotech Fellowship: A Test of Alternative Speciation Hypotheses Using Molecular Systematic Analysis of Lagenorhynchus Dolphins.

小行星9213281 在一个明显的热带屏障的北部和南部发现了各种相关的海洋和陆地植物和动物类群。 这些“反热带”分类群的多样性包括许多假定的鲸鱼、海豚和鼠海豚的种群或物种对。 该项目将研究在北方和南方温带海洋发现的Lagerichynchus属海豚物种之间的关系和差异，并将检验更新世冰川作用或中新世中期变暖的替代假设，以解释目前观察到的反热带物种分布。 部分海豚线粒体DNA的序列分析，补充使用核DNA标记，将被用来建立属内的关系，并比较相关的外群属内的家庭海豚科。为了将大量的遗传分歧发现Lagerichynchus物种之间的角度来看，这将是必要的序列标本从种群内Lagerichynchus物种提供一个尺度来解释种间分歧。 本研究亦将探讨白色侧海豚（L.在北太平洋连续分布的海豚，以及广泛分离的黑海豚（L。obscurus）来自南大洋。 这将是首次尝试建立这些物种的遗传标准，以区分股票，或承认潜在的特定地位的L。来自不同地区的obscurus。这一信息可能有助于确定某些种群是否受到某些区域捕捞活动的威胁。 为了评估大致的时间Lagerichynchus物种之间的分歧，遗传距离将被解释使用人口结构分析，比较公布的序列外群，并比较已知的其他类群的遗传距离在中新世和更新世的时间diverged提供的观点。由于这两种选择的时间尺度之间的差异很大，因此即使没有速率校准，也可以识别Lagerhynchus发散时间与之一致。 ***

9213281 Cipriano A variety of related plant and animal taxa, both marine and terrestrial, are found to the north and south of an apparent tropical barrier. The variety of these "antitropical" taxa includes many supposed populations or species pairs of whales, dolphins and porpoises. This project will study the relationships and divergence between dolphin species of the genus Lagenorhynchus found in northern and southern temperate oceans and will test alternative hypotheses of Pleistocene glaciation or mid-Miocene warming as explanations for the currently observed anti-tropical species distributions. Sequence analysis of portions of dolphin mitochondrial DNA, with supplemental use of nuclear DNA markers, will be used to establish relationships within the genus, and for comparison to related outgroup genera also within the the Family Delphinidae. In order to place amounts of genetic divergence found between Lagenorhynchus species into perspective, it will be necessary to sequence specimens from populations within Lagenorhynchus species to provide a yardstick for interpreting interspecific divergence. This project will also investigate the population structure of white- sided dolphins (L. obliquidens) found continuously distributed in the North Pacific, and of widely separated populations of dusky dolphins (L. obscurus) from the southern oceans. This would be the first attempt to establish genetic criteria for distinction of stocks of these species, or to recognize potential specific status of L. obscurus from different areas. This information may be useful to determine whether particular stocks are at risk form fishing activities in certain regions. In order to assess the approximate timing of the divergence between Lagenorhynchus species, genetic distances will be interpreted using the perspective provided by population structure analysis, comparison to published sequences for outgroups, and comparison to genetic distances of other taxa known to have div erged in Miocene and Pleistocene times. Because of the large difference between the time scale of the two alternatives, identification of the congruence of Lagenorhynchus divergence timing with one should thus be possible even without a rate calibration. ***