A simple method for bracketing absolute divergence times on molecular phylogenies using multiple fossil calibration points
A simple method for bracketing absolute divergence times on molecular phylogenies using multiple fossil calibration points
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DOI：
10.1086/587523
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发表时间：
2008-06-01
影响因子：
2.9
通讯作者：
Marshall, Charles R.
中科院分区：
文献类型：
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作者：
Marshall, Charles R.
分子系统发育的时间校准面临的一个主要挑战是找到一种定量方法来估计谱系分歧时间的最大年龄限制。在这里，我提供这样一个方法。该方法需要在不参考化石记录的情况下生成超测量树。利用超测量树上的相对分支长度与时间成正比的事实，该方法识别出化石记录所覆盖的真实时间范围中比例最大的谱系。该校准谱系中最古老的化石被用作最小年龄限制。最大年龄约束是通过在校准谱系的终点上添加置信区间来获得的，从而可以将树上所有谱系的真实分歧时间括起来。该方法还可以识别年代严重错误或错误分配到系统发育的化石。该方法假设超测量树上的相对分支长度是准确的并且化石化是随机的。评估违反这些假设的影响。该方法使用简单，并通过对 Near 等人的海龟数据的重新分析进行说明。
A central challenge facing the temporal calibration of molecular phylogenies is finding a quantitative method for estimating maximum age constraints on lineage divergence times. Here, I provide such a method. This method requires an ultrametric tree generated without reference to the fossil record. Exploiting the fact that the relative branch lengths on the ultrametric tree are proportional to time, this method identifies the lineage with the greatest proportion of its true temporal range covered by the fossil record. The oldest fossil of this calibration lineage is used as the minimum age constraint. The maximum age constraint is obtained by adding a confidence interval onto the end point of the calibration lineage, thus making it possible to bracket the true divergence times of all lineages on the tree. The approach can also identify fossils that have been grossly misdated or misassigned to the phylogeny. The method assumes that the relative branch lengths on the ultrametric tree are accurate and that fossilization is random. The effect of violations of these assumptions is assessed. This method is simple to use and is illustrated with a reanalysis of Near et al.'s turtle data.