Rocks and clocks: linking geologic history and rates of genetic differentiation in anchialine organisms
Rocks and clocks: linking geologic history and rates of genetic differentiation in anchialine organisms
复制标题
岩石和时钟：将地质历史和近生生物的遗传分化率联系起来
作者：
S. R. Santos;D. Weese
一个地区的地质历史可以显著影响其动植物的发展，过去的事件塑造了群落模式和物种的进化轨迹。在这方面，岛屿由于其离散的地理性质和动态地质历史，是研究基本进化过程的极好“自然实验室”。夏威夷群岛是一个符合这些标准的岛屿系统，它是测试岛屿地质历史如何影响导致种群遗传变异和分化的过程的理想场所。有一种夏威夷特有的动物，其进化史与岛上的地质情况密切相关，那就是嗜盐无碱虾，它的线粒体细胞色素氧化酶I （COI）基因被假设以每百万年20%的速度进化。为了验证这种快速的进化速度，从地理上接近但基因上不同的差异估计开始的时间，研究人员计算了来自夏威夷、毛伊岛和奥胡岛上的动物栖息地的Halocaridina种群。在较年轻（即小于150万年）的夏威夷岛和毛伊岛，所有的甲藻栖息地都发生在玄武岩中，应用Halocaridina分子钟确定了遗传分化水平与这些种群居住地区的地质年龄之间的强烈相关性。相比之下，当对更古老（即275万年前）的O’ahu岛上的石灰岩anchialine栖息地的Halocaridina进行类似分析时，这种关系就减弱了。这些结果表明，地质年龄、盆地起源和/或组成是进行分子钟分析时应该考虑的重要因素。
The geologic history of a region can significantly impact the development of its flora and fauna, with past events shaping community patterns and evolutionary trajectories of species. In this context, islands are excellent “natural laboratories” for studying the fundamental processes of evolution due to their discrete geographical nature and dynamic geologic histories. An island system meeting these criteria is the Hawaiian Archipelago, which is ideal for testing how island geologic history influences the processes leading to population genetic variation and differentiation. One Hawaiian endemic whose evolutionary history is closely tied to the geology of the islands is the anchialine atyid shrimp Halocaridina, whose mitochondrial cytochrome oxidase I (COI) gene is hypothesized to be evolving at the rate of 20% per million years. To validate this rapid evolutionary rate, time since divergence estimates between geographically close, yet genetically distinct, populations were calculated for Halocaridina from anchialine habitats on the islands of Hawai’i, Maui, and O’ahu. On the younger (i.e., <1.5 million years) islands of Hawai’i and Maui, where all anchialine habitats occur in basalt, application of the Halocaridina molecular clock identified a strong correlation between levels of genetic divergence and the geologic age of the region inhabited by those populations. In contrast, this relationship weakened when similar analyses were conducted for Halocaridina from limestone anchialine habitats on the older (i.e., >2.75 million years) island of O’ahu. These results suggest geologic age, basin origin and/or composition are important factors that should be taken into consideration when conducting molecular clock analyses on anchialine flora and fauna as well as island populations in general.
影响因子：
3.3
作者：
Yunxin Fu
通讯作者：
Yunxin Fu