Collaborative Research: Evolution of Population Connectivity in Sea Stars

博士。图宁和格罗斯伯格将研究世界各地浅温带和热带海洋中发现的海星（海星科，或蝙蝠星）的种群遗传变异和繁殖。 海洋种群遗传变异在很大程度上可以用扩散差异来解释：种群之间强烈的遗传漂变、局部近亲繁殖、频繁的局部灭绝以及没有浮游幼虫的物种的局部适应潜力；幼虫广泛传播的物种基因流强，遗传漂变小，近亲繁殖有限，物种形成或灭绝的机会较少。然而，最近使用不同遗传标记对各种生物和海洋进行的研究表明，这种观点是有限的。除了洋流中的扩散之外的过程可能对种群遗传结构产生主要影响。许多物种可能不会在扩散、基因流、突变和遗传漂变之间达到群体遗传平衡。这项研究将有助于测试这些预期，并通过以下方式扩大海洋种群遗传变异的视野：（1）使用不同蝙蝠星谱系和生命周期改变的物种的多个基因来比较种群结构； (2) 评估其他生命周期差异（特别是自交和体内受精）对群体遗传模式的贡献； （3）利用物种之间已知的系统发育关系来询问生命周期特征的趋同进化导致相似群体遗传模式的频率； (4) 评估历史过程的贡献，例如地理范围扩张、气候变化或最近的物种形成事件，这些事件可能使种群遗传模式偏离基于扩散潜力的预期模式； (5) 估计基因流和种群结构对配子之间（受精时）或基因组之间（幼虫发育期间）生殖不相容进化的影响。研究人员和他们的学生将加入加拿大和澳大利亚研究人员的既定合作。来自所有四个机构的女性、夏威夷本地人和澳大利亚原住民学生研究人员将在不同的领域（阿拉斯加、不列颠哥伦比亚省、加利福尼亚州、巴哈、昆士兰州、新南威尔士州）和实验室环境中工作。这些学生将培养分子遗传学、定量分析、系统发育学和生殖生物学的综合技能。如果以前的研究有任何指导意义的话，那么结果可能会通过识别新的神秘物种来促进海洋生物多样性的基本知识。比较种群遗传分析将帮助海洋生态学家和保护生物学家了解有助于种群结构和当地遗传多样性的因素组合。这些知识对于诸如加利福尼亚州海洋保护区的位置和管理、一些受到沿海开发和有毒入侵物种威胁并已被授予保护地位的澳大利亚濒危海燕的保护状况等问题至关重要；以及拟建的夏洛特皇后群岛瓜伊哈纳斯世界遗产地中海洋生物的独特遗传特性。

Drs. Toonen and Grosberg will study population genetic variation and reproduction in sea stars (Asterinidae, or bat stars) found in shallow temperate and tropical oceans around the world. Marine population genetic variation has largely been interpreted in terms of dispersal differences: strong genetic drift among populations, local inbreeding, frequent local extinction, and potential for local adaptation in species without planktonic larvae; strong gene flow, little genetic drift, limited inbreeding, and fewer opportunities for speciation or extinction in species with widespread larval dispersal. However, recent studies in various organisms and oceans using diverse genetic markers suggest that this view is limited. Processes other than dispersal in ocean currents may have a predominant influence on population genetic structure. Many species may not be expected to approach population genetic equilibrium between dispersal, gene flow, mutation, and genetic drift. This research will help to test these expectations and expand the view of population genetic variation in the ocean by (1) comparing population structure using multiple genes for different bat star lineages and species with modified life cycles; (2) assessing the contribution of other life cycle differences (especially selfing and internal fertilization) to population genetic patterns; (3) using known phylogenetic relationships among species to ask how often convergent evolution of life cycle traits has resulted in similar population genetic patterns; (4) evaluating the contribution of historical processes such as geographical range expansion, climate change, or recent speciation events that could push population genetic patterns away from expected patterns based on dispersal potential; (5) estimating the impact of gene flow and population structure on the evolution of reproductive incompatibility between gametes (at fertilization) or between genomes (during larval development). The investigators and their students will join an established collaboration involving Canadian and Australian researchers. Female, native Hawaiian, and Australian Aboriginal student researchers from all four institutions will work in diverse field (Alaska, British Columbia, California, Baja, Queensland, New South Wales) and lab settings. These students will develop a combination of skills in molecular genetics, quantitative analysis, phylogenetics, and reproductive biology. If previous studies are any guide, the results are likely to contribute to basic knowledge of biological diversity in the ocean by identifying new cryptic species. The comparative population genetic analysis will help marine ecologists and conservation biologists understand the mix of factors that contribute to population structure and local genetic diversity. Such knowledge is crucial to issues such as the location and management of marine protected areas in California, the conservation status of some endangered Australian asterinids that are threatened by coastal development and noxious invasive species and have been given protected status; and the unique genetic properties of the marine organisms in the proposed Gwaii Haanas World Heritage Site in the Queen Charlotte Islands.