Testing the spatial and temporal framework of speciation in an ancient lake species flock
Testing the spatial and temporal framework of speciation in an ancient lake species flock
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测试古代湖泊物种群中物种形成的时空框架
DOI：
10.5194/bgd-7-5011-2010
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发表时间：
2010
期刊：
影响因子：
4.9
通讯作者：
T. Wilke
中科院分区：
文献类型：
--
作者：
S. Trajanovski;C. Albrecht;K. Schreiber;R. Schultheiß;T. Stadler;M. Benke;T. Wilke
巴尔干半岛上的古奥赫里德湖被认为是欧洲最古老的古湖，其年代可能在上新世到更新世之间。然而，其确切的地质年代仍然未知。因此，奥赫里德湖生物群的分子钟数据可以作为现有地质数据的独立约束，从而也可以帮助改进年龄估计。这些进化数据也可能有助于揭示促进物种形成事件的潜在生物和非生物因素。本文利用奥赫里德湖最大的特有类群之一——水蛭属Dina的线粒体测序数据，测试它是否代表了一个古老的湖泊物种群，研究奥赫里德湖水平和垂直屏障对进化事件的作用，并基于分子钟分析估计该群体的湖内多样化的开始。并将这些数据与其他特有物种的数据进行比较，为奥赫里德湖的起源提供一个大致的时间框架。根据物种特征、单系特征和特有特征，认为奥赫里德迪纳湖确实是一个古老的湖泊物种群。然而，其物种的谱系分类似乎并不完整。对奥赫里德流域Dina spp.种群结构的分析表明，泉水和湖泊种群的单倍型呈水平带状分布，证实了湖边泉水，特别是南部水源泉在奥赫里德特有分类群进化过程中的作用。然而，湖泊分类群的垂直分化似乎是有限的，尽管沿海和深海种群之间的差异是明显的。分子钟分析表明，该群现存物种最近的共同祖先年龄约为1.99±0.83 Ma，而Ohrid Dina湖群从湖外一个潜在的姐妹类群中分裂出来的时间估计为8.30±3.60 Ma。与其他特有种类群的比较表明，在所有情况下，池内多样化开始于≤2 Ma以前。因此，这一估计可能提供有关奥赫里德湖起源的最低年龄的信息。最大年龄不太一致，通常不太可靠。但谨慎地说，建议最大年龄为3 Ma。有趣的是，奥赫里德湖起源的时间框架约为2-3 Ma，仅基于进化数据生成，与地质学家文献中最常用的时间框架非常吻合。未来的研究必须证明这种一致性是否成立。
Ancient Lake Ohrid on the Balkan Peninsula is considered to be the oldest ancient lake in Europe with a suggested Plio-Pleistocene age. Its exact geological age, however, remains unknown. Therefore, molecular clock data of Lake Ohrid biota may serve as an independent constraint of available geological data, and may thus also help to refine age estimates. Such evolutionary data may also help unravel potential biotic and abiotic factors that promote speciation events. Here, mitochondrial sequencing data of one of the largest groups of endemic taxa in Lake Ohrid, the leech genus Dina, is used to test whether it represents an ancient lake species flock, to study the role of horizontal and vertical barriers in Lake Ohrid for evolutionary events, to estimate the onset of intralacustrine diversification in this group based on molecular clock analyses, and to compare this data with data from other endemic species for providing an approximate time frame for the origin of Lake Ohrid. Based on the criteria speciosity, monophyly and endemicity, it can be concluded that Lake Ohrid Dina, indeed, represents an ancient lake species flock. Lineage sorting of its species, however, does not seem to be complete. Analyses of population structures of Dina spp. in the Ohrid watershed indicate a horizontal zonation of haplotypes from spring and lake populations, corroborating the role of lake-side springs, particularly the southern feeder springs, for evolutionary processes in endemic Ohrid taxa. Vertical differentiation of lake taxa, however, appears to be limited, though differences between populations from the littoral and the profundal are apparent. Molecular clock analyses indicate that the most recent common ancestor of extant species of this flock is approximately 1.99±0.83 Ma old, whereas the split of the Lake Ohrid Dina flock from a potential sister taxon outside the lake is estimated at 8.30±3.60 Ma. Comparisons with other groups of endemic Ohrid species indicated that in all cases, intralacustrine diversification started ≤2 Ma ago. Thus, this estimate may provide information on a minimum age for the origin of Lake Ohrid. Maximum ages are less consistent and generally less reliable. But cautiously, a maximum age of 3 Ma is suggested. Interestingly, this time frame of approximately 2–3 Ma for the origin of Lake Ohrid, generated based solely on evolutionary data, well fits the time frame most often used in the literature by geologists. Future studies must show whether this concurrence holds true.