Centre for Macroevolution and Macroecology, Division of Ecology, Evolution and Genetics, Research School of Biology, Australian National University, Canberra, ACT 0200, Australia
Centre for Macroevolution and Macroecology, Division of Ecology, Evolution and Genetics, Research School of Biology, Australian National University, Canberra, ACT 0200, Australia.
Syst Biol. 2016 Jan;65(1):109-27. doi: 10.1093/sysbio/syv062. Epub 2015 Oct 10.
Phylogenetic analyses have lent support to the concept of lineage selection: that biological lineages can have heritable traits that influence their capacity to persist and diversify, and thereby affect their representation in biodiversity. While many discussions have focused on "positive" lineage selection, where stably heritable properties of lineages enhance their diversification rate, there are also intriguing examples that seem to represent "negative" lineage selection, where traits reduce the likelihood that a lineage will persist or speciate. In this article, we test whether a particular pattern of negative lineage selection is detectable from the distributions of the trait on a phylogeny. "Self-destructive" traits are those that arise often but then disappear again because they confer either a raised extinction rate or they are prone to a high rate of trait loss. For such a trait, the reconstructed origins will tend to be dispersed across the tips of the phylogeny, rather than defining large clades of related lineages that all share the trait. We examine the utility of four possible measures of "tippiness" as potential indicators of macroevolutionary self-destruction, applying them to phylogenies on which trait evolution has been simulated under different combinations of parameters for speciation, extinction, trait gain, and trait loss. We use an efficient simulation approach that starts with the required number of tips with and without the trait and uses a model to work "backwards" to construct different possible trees that result in that set of tips. We then apply these methods to a number of case studies: salt tolerance in grasses, color polymorphism in birds of prey, and selfing in nightshades. We find that the relative age of species, measured from tip length, can indicate a reduced speciation rate but does not identify traits that increase the extinction rate or the trait loss rate. We show that it is possible to detect cases of macroevolutionary self-destruction by considering the number of tips with the trait that arise from each inferred origin, and the degree to which the trait is scattered across the phylogeny. These metrics, and the methods we present, may be useful for testing macroevolutionary hypotheses from phylogenetic patterns.
生物谱系可以具有遗传特征，这些特征影响它们持续存在和多样化的能力，从而影响它们在生物多样性中的表现。虽然许多讨论都集中在“正向”谱系选择上，即谱系中稳定遗传的特性会提高其多样化率，但也有一些有趣的例子似乎代表了“负向”谱系选择，即特征降低了谱系持续存在或形成新物种的可能性。在本文中，我们测试了从系统发育树上的特征分布中是否可以检测到特定的负向谱系选择模式。“自我毁灭”特征是指那些经常出现但又再次消失的特征，因为它们要么导致灭绝率升高，要么容易导致特征丢失率升高。对于这样的特征，重建的起源往往会分散在系统发育树的顶端，而不是定义所有具有该特征的相关谱系的大分支。我们检验了四种可能的“尖端”度量作为宏观进化自我毁灭的潜在指标的有效性，将它们应用于在不同的物种形成、灭绝、特征获得和特征丢失参数组合下模拟特征进化的系统发育树上。我们使用一种有效的模拟方法，该方法从具有和不具有特征的所需数量的顶端开始，并使用模型“向后”构建产生该顶端集的不同可能的树。然后，我们将这些方法应用于一些案例研究：禾本科植物的耐盐性、猛禽的颜色多态性和茄科植物的自交。我们发现，从顶端长度衡量的物种相对年龄可以指示出降低的物种形成率，但无法识别增加灭绝率或特征丢失率的特征。我们表明，通过考虑从每个推断的起源出现的具有特征的顶端数量以及特征在系统发育树上的分散程度，可以检测到宏观进化的自我毁灭情况。这些指标和我们提出的方法可能有助于从系统发育模式中检验宏观进化假说。
