主流分子钟定年方法的原理、误差来源和使用建议

陈旸康, 王益, 李家亮, 王文韬, 冯端宇, 毛康珊

Principles, error sources and application suggestions of prevailing molecular dating methods

Yangkang Chen, Yi Wang, Jialiang Li, Wentao Wang, Duanyu Feng, Kangshan Mao

图5 节点年龄的概率分布。在不同节点设置最大或最小年龄限制, 可以采用不同的概率分布。其中(a)图表示系统发育树上设置最小和最大年龄限制的两个节点, (b)-(f)强调均匀、正态、伽马、对数正态和指数分布中的最小年龄限制, 而(g)和(h)则分别表示了均匀分布中的严格和宽松最大年龄限制(虚线及虚线框)。另外, (c)-(f)中虚线框强调的部分等同于宽松最大年龄限制。图中的soft maximum/minimum constraint又称软边界(soft bound)。

Fig. 5 Probability distribution of node age. The maximum or minimum age constraint can be set on different nodes, and different probability distribution can be adopted. Where (a) shows two nodes with minimum and maximum age constraint, respectively, in phylogenetic tree; (b)-(f) emphasize the minimum age constraints in uniform, normal, gamma, lognormal and exponential distribution, while (g) and (h) represent strict and relaxed maximum age constraints on uniform distribution, respectively. In addition, the part highlighted by the dotted box in (c)-(f) is equivalent to the relaxed maximum age constraint. The soft maximum/minimum constraint in the figure is also called soft bound.