U.S.-Japan Dissertation Enhancement: Speciation with Hybridization: The case of Japanese Hexagrammids

0123805Bernardi该奖项支持加州大学圣克鲁斯分校的Giacomo Bernardi教授和Karen Crow教授、日本北海道大学的Hiroyuki Munehara教授以及符拉迪沃斯托克俄罗斯科学院的Andrey Balanov教授之间为期一年的合作研究项目。研究人员将进行一项涉及日本六角菊物种形成与杂交的研究。强化是异域物种二次接触后自然选择对杂交种的选择性交配的结果。从理论上讲，强化可能是驱动物种形成的重要力量。在实验室实验中很难产生强化的证据，而且在自然环境中，特别是在海洋系统中缺乏研究。然而，在过去的五年中，理论和实证支持不断增加，需要做更多的研究来进一步验证这些预测。六角鱼属的鱼类符合理论的标准，有利于通过强化形成物种。这项研究将包括测试同型交配是否与杂交种适应度降低相结合，以确定在这个系统中，强化是否是维持物种边界的重要力量。提出的研究的主要焦点是确定杂交在物种形成过程中的作用。具体目标是：1)描述日本北海三个地点自然发生的杂交品种的相对比例；2)通过估算杂交、特异和f1杂交回交产生的幼虫的适应度差异成本来衡量亲本物种之间的合子后生殖隔离；3)通过比较同域和异域种群亲本物种的分类交配选择差异来估计合子前生殖隔离。该项目汇集了三个具有互补专业知识和研究能力的国际实验室的努力。在进化生物学中，早熟隔离的强化过程引起了极大的兴趣。这项研究的结果可能会为我们对物种形成过程的理解提供重大贡献，特别是在作为物种形成机制的强化领域。该项目通过研究生的参与促进了国际人力资源。通过思想和技术的交流，该项目将扩大我们的基础知识基础，促进国际了解与合作。研究人员计划在科学期刊上发表研究结果，并在科学会议上报告研究结果。

0123805BernardiThis award supports a one-year collaborative research project between Professor Giacomo Bernardi and Karen Crow at the University of California, Santa Cruz and Professor Hiroyuki Munehara of Hokkaido University in Japan as well as Professor Andrey Balanov of the Russian Academy of Sciences in Vladivostok. The researchers will undertake a study of the involvement of speciation with hybridization of the Japanese Hexagrammids. Reinforcement is the build up of assortative mating resulting from natural selection against hybrids upon secondary contact of allopatric species. It has been theorized that reinforcement could be an important force driving speciation. Evidence for reinforcement in laboratory experiments has been difficult to generate, and studies in natural settings have been lacking, especially in marine systems. However, theoretical and empirical support has grown in the last five years and additional studies need to be done to further test these predictions. Fishes of the genus Hexagrammos meet criteria theorized to favor speciation by reinforcement. The research will involve testing whether assortative mating is being built up in conjunction with reduced fitness of hybrids to determine if reinforcement is an important force maintaining species boundaries in this system. The main focus of the proposed research is to determine the role of hybridization in processes of speciation within the genus Hexagrammos. The specific goals are to: 1) characterize the relative proportions of hybrids occurring in nature at three sites in the Northern Sea of Japan; 2) measure post-zygotic reproductive isolation between parental species by estimating differential costs in fitness associated with larvae produced from hybrid, specific and F1-hybrid backcrosses; and 3) estimate pre-zygotic reproductive isolation by comparing differences in assortative mate selection in parental species from both sympatric and allopatric populations.The project brings together the efforts of three international laboratories that have complementary expertise and research capabilities. The process of reinforcement of premating isolation is of great interest in evolutionary biology. Results of this research are likely to provide a major contribution to our understanding of speciation processes, particularly in the area of reinforcement as a mechanism for speciation. The project advances international human resources through the participation of a graduate student. Through the exchange of ideas and technology, this project will broaden our base of basic knowledge and promote international understanding and cooperation. The researchers plan to publish results of the research in scientific journals and report on the findings at scientific meetings.