Molecular Analysis of Morphologically Defined Taxa in the Montastraea Annularis Complex

Montastraea Annularis 复合体中形态学定义类群的分子分析

• 批准号: 9811124
• 负责人: Nancy Knowlton
• 金额: $ 24.87万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-10-01 至 2003-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9811124&HistoricalAwards=false
• 关键词: Molecular; Analysis; Morphologically; Defined; Taxa

Failure to accurately define and identify species fundamentally compromises our ability to understand and manage marine ecosystems. The problem is particularly acute on reefs, where there is no consensus on the species status of the numerous ecologically and morphologically distinct `forms` that comprise many important groups of corals. While the problematic nature of coral species is widely recognized, there is no consensus as to why this problem exists. Some scientists argue that extensive and complex patterns of hybridization make species boundaries arbitrary in corals, but the data to test this assertion are largely lacking, particularly for Caribbean corals. In this project, Dr. Knowlton and collaborators will tackle this problem using the star coral, Montastraea annularis, as a model system. This coral is the most abundant coral of the Caribbean, and has been for millions of years. It has been extensively studied by biologists and geologists as a kind of `lab rat` for a wide variety of studies (e.g. coral bleaching, paleoclimatology), but recent results suggest that what had been viewed as a single polymorphic species may represent a complex of at least three reproductively isolated forms that can be identified by their colony morphologies. Previous work was on coral genetics, symbiosis, morphometrics and reproductive biology but the genetic patterns on wide geographic scales are of fundamental importance. If the three taxa comprising Montastraea annularis do not routinely interbreed, then fixed diagnostic differences should in principle be detectable. Dr. Knowlton has already uncovered a few fixed or nearly fixed differences using amplified fragment length polyinorphism (AFLP) and restriction fragment length polymorphism (RFLP) between M. faveolata and the other two taxa. She has as yet found no fixed genetic differences between M. annularis and M. franksi, but they appear to spawn at distinct times throughout their range, suggesting that they are not genetically identical. In this project, she will continue to screen for genetic differences among these taxa, in order to determine if hybrids between M. faveolata and the other taxa can be detected and to see if more extensive searches will reveal differences between M. annularis and M. franksi. She will also extend the genetic analyses from Panama to other sites in the Caribbean, to determine if the patterns observed here are also seen elsewhere. This will be the first such genetic analysis of a reef coral species complex throughout its geographic range.

未能准确定义和识别物种从根本上损害了我们理解和管理海洋生态系统的能力。这个问题在珊瑚礁上尤其严重，对于构成许多重要珊瑚群的众多生态和形态上不同的“形式”的物种状况尚未达成共识。虽然珊瑚物种的问题性质已得到广泛认可，但对于为什么存在这个问题尚未达成共识。 一些科学家认为，广泛而复杂的杂交模式使得珊瑚的物种边界变得任意，但检验这一论断的数据基本上缺乏，特别是对于加勒比珊瑚。 在这个项目中，诺尔顿博士和合作者将使用星形珊瑚 Montastraea ringis 作为模型系统来解决这个问题。这种珊瑚是加勒比地区最丰富的珊瑚，已有数百万年的历史。生物学家和地质学家将其作为一种“实验室老鼠”进行了广泛的研究（例如珊瑚白化、古气候学），但最近的结果表明，被视为单一多态性物种的物种可能代表了至少三种生殖隔离形式的复合体，这些形式可以通过其群体形态来识别。 以前的工作是关于珊瑚遗传学、共生、形态测量学和生殖生物学，但广泛地理范围内的遗传模式至关重要。 如果构成环山山的三个分类群不经常杂交，那么固定的诊断差异原则上应该是可检测到的。 Knowlton 博士已经利用扩增片段长度多态性 (AFLP) 和限制性片段长度多态性 (RFLP) 发现了 M. faveolata 和其他两个类群之间的一些固定或几乎固定的差异。她尚未发现环状巨藻和弗兰克氏巨藻之间没有固定的遗传差异，但它们似乎在整个分布范围内的不同时间产卵，这表明它们在基因上并不相同。 在这个项目中，她将继续筛选这些类群之间的遗传差异，以确定是否可以检测到 M. faveolata 和其他类群之间的杂交，并看看更广泛的搜索是否会揭示 M.环状和 M. Franksi 之间的差异。 她还将把基因分析从巴拿马扩展到加勒比海的其他地点，以确定这里观察到的模式是否也在其他地方出现。这将是首次对整个地理范围内的珊瑚礁物种复合体进行此类遗传分析。