DISSERTATION RESEARCH: Phylogeny of the Genus Microlophus (Squamata: Tropiduridae): A History of Colonization and Dispersal

论文研究：Microlophus 属（有鳞目：Tropiduridae）的系统发育：定殖和扩散的历史

• 批准号: 0309111
• 负责人: Jack Sites
• 金额: $ 1.2万
• 依托单位: Brigham Young University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-06-15 至 2004-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0309111&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; Phylogeny; Genus; Microlophus

A grant has been awarded from the National Science Foundation to Dr. Jack Sites and Mr. Edgar Benavides, Brigham Young University, to study the "Phylogeny of the South American lizard genus Microlophus." This genus consists of 22 recognized species with an extremely unusual geographic distribution; 9 species are found only in the Galapagos islands, ~ 1000 km off the west coast of Ecuador in the eastern Pacific, while the remaining 13 species occur in western South America from southern Ecuador to central Chile. Most of the mainland species are confined to the Atacama Desert within a few km of the coast, and thus occupy a linear 'strip' of habitat almost 5000 km long. This distribution is absolutely unique among land vertebrates. The main objective of the study will be to reconstruct the evolutionary relationships of all species in this group using DNA sequences from seven different gene regions, and computer-assisted tree-building algorithms to test the strength of support for specific genealogical groups identified in the trees. The project is broadly significant for two reasons. First, earlier studies have suggested that ancestors of the mainland species of this group have colonized the Galapagos independently on two occasions, but none of these studies have been based on sampling of all mainland species, so results can be explained as possibly spurious consequences of incomplete sampling. Benavides has now collected all recognized mainland species, and can overcome this criticism with more statistically powerful analyses that were not available to earlier investigators. Second, there are at least three alternative scenarios for the sequence of coloniazation of islands within the Galapagos Archipelago, but again sampling limitations have not permit a rigorous evaluation of alternatives. Sites and Benavides have obtained all but two of the Galapagos taxa, and will collect the missing species during this study; this more complete sampling design coupled with extensive molecular data will give a clearer picture, based on statistically robust hypotheses, for the assembly and evolution of the unique Galapagos fauna.

美国国家科学基金会已向杨百翰大学的杰克·斯特斯博士和埃德加·贝纳维德斯先生提供一笔赠款，用于研究“南美蜥蜴属的系统发育”。该属由22个公认的物种组成，具有极不寻常的地理分布; 9个物种仅在东太平洋厄瓜多尔西海岸约1000公里的加拉帕戈斯群岛发现，而其余13个物种则分布在南美洲西部，从厄瓜多尔南部到智利中部。 大部分的大陆物种被限制在阿塔卡马沙漠的海岸几公里内，因此占据了一个线性的“带”的栖息地近5000公里长。这种分布在陆地脊椎动物中是绝对独特的。 这项研究的主要目的是利用来自七个不同基因区域的DNA序列重建该组中所有物种的进化关系，并利用计算机辅助树构建算法来测试树中确定的特定谱系组的支持强度。 该项目具有广泛的意义，原因有二。 首先，早期的研究表明，这一群体的大陆物种的祖先曾两次独立地殖民于加拉帕戈斯，但这些研究都没有基于对所有大陆物种的采样，因此结果可以解释为不完整采样的可能虚假结果。 贝纳维德斯现在已经收集了所有公认的大陆物种，并且可以通过更强大的统计分析来克服这种批评，这些分析是早期研究人员无法获得的。 第二，对于加拉帕戈斯群岛内岛屿的殖民化顺序，至少有三种备选方案，但同样由于取样的限制，无法对备选方案进行严格的评价。 Sites和Benavides已经获得了除两个之外的所有加拉帕戈斯分类群，并将在本研究期间收集缺失的物种;这种更完整的采样设计加上广泛的分子数据将根据统计学上可靠的假设，为独特的加拉帕戈斯动物群的组装和进化提供更清晰的画面。