Age and rate of diversification of the Hawaiian silversword alliance (Compositae)
Age and rate of diversification of the Hawaiian silversword alliance (Compositae)
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DOI：
10.1073/pnas.95.16.9402
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发表时间：
1998-08-04
影响因子：
11.1
通讯作者：
Sanderson, MJ
中科院分区：
文献类型：
--
作者：
Baldwin, BG;Sanderson, MJ
岛屿和大陆辐射之间的比较受到阻碍，缺乏可靠的估计绝对多样化率岛屿血统。我们利用速率常数rDNA序列进化和“外部”校准使用古气候和化石数据，以确定夏威夷银剑联盟（菊科），一个教科书的例子岛屿适应性辐射植物的最大年龄和最小多样化率。我们对银剑联盟最近的共同祖先的最大年龄估计为520 +/-80万年前，这比夏威夷果蝇、半边莲和采蜜鸟的其他方法计算的年龄要年轻得多，而且福尔斯大约在现代高地群岛的历史范围内（小于或等于5.1 +/- 0.2百万年前），通过使用统计上有效的估计，通过结合基于时钟的发散时间估计来减少误差方差，银剑联盟的最低多样化率估计为每百万年0.56 +/- 0.17个物种。这超过了更古老的大陆辐射的平均速率，与具有足够丰富的化石记录的类群的峰值速率相当，可以重建多样化速率的变化。
Comparisons between insular and continental radiations have been hindered by a lack of reliable estimates of absolute diversification rates in island lineages. We took advantage of rate-constant rDNA sequence evolution and an "external" calibration using paleoclimatic and Fossil data to determine the maximum age and minimum diversification rate of the Hawaiian silversword alliance (Compositae), a textbook example of insular adaptive radiation in plants. Our maximum-age estimate of 5.2 +/- 0.8 million years ago for the most recent common ancestor of the silversword alliance is much younger than ages calculated by other means for the Hawaiian drosophilids, lobelioids, and honeycreepers and falls approximately within the history of the modern high islands (less than or equal to 5.1 +/- 0.2 million years ago), By using a statistically efficient estimator that reduces error variance by incorporating clock-based estimates of divergence times, a minimum diversification rate for the silversword alliance was estimated to be 0.56 +/- 0.17 species per million years. This exceeds average rates of more ancient continental radiations and is comparable to peak rates in taxa with sufficiently rich fossil records that changes in diversification rate can be reconstructed.