A robust new metric of phenotypic distance to estimate and compare multiple trait differences among populations
A robust new metric of phenotypic distance to estimate and compare multiple trait differences among populations
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一种强大的新表型距离度量，用于估计和比较群体之间的多种性状差异
DOI：
10.1093/czoolo/58.3.426
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发表时间：
2012
期刊：
影响因子：
2.2
通讯作者：
UY J.AlbertC.
中科院分区：
文献类型：
--
作者：
R. Safran;S. Flaxman;M. Kopp;D. Irwin;Derek C. Briggs;M. Evans;W. Funk;D. A. Gray;E. Hebets;N. Seddon;Elizabeth S. C. Scordato;L. Symes;J. Tobias;D. P. Toews;UY J.AlbertC.
§ 平等贡献。摘要 尽管存在丰富的文献来估计群体遗传差异，但缺乏表型性状差异的度量，特别是在比较三个或更多群体之间的多个性状时。在这里，我们通过模拟回顾和分析 Hedges g，一种广泛使用的效应大小参数估计。我们的分析表明，g 对群体中不等的性状方差和不等的样本量的组合以及测量规模的变化敏感。然后，我们继续推导并解释一个新的非参数距离度量“Δp”，它是根据所有研究人群的联合累积分布函数（CDF）计算的。更准确地说，距离是根据每个总体中位数所在 CDF 中的百分位数来测量的。 Δp 将其他距离度量的许多所需特征组合成一个度量；也就是说，与其他指标相比，p 对抽样总体之间的不平等方差和样本量相对不敏感。此外，Δp 的一个关键特征（也是我们开发它的主要动机）是，它可以轻松地同时比较任意数量人群中的任意数量的性状。为了举例说明其效用，我们使用 Δp 来解决与性选择在物种形成中的作用相关的问题：在密切相关的类群中，性信号是否比生态特征更加不同？利用密切相关的种群中已知功能的特征，我们表明，预测繁殖性能的特征实际上比与生态适应相关的特征更加分歧和更加两性异形（Current Zoology 58 (3): 426-439, 2012）。
§ Equal contribution. Abstract Whereas a rich literature exists for estimating population genetic divergence, metrics of phenotypic trait divergence are lacking, particularly for comparing multiple traits among three or more populations. Here, we review and analyze via simula- tion Hedges' g, a widely used parametric estimate of effect size. Our analyses indicate that g is sensitive to a combination of un- equal trait variances and unequal sample sizes among populations and to changes in the scale of measurement. We then go on to derive and explain a new, non-parametric distance measure, "Δp", which is calculated based upon a joint cumulative distribution function (CDF) from all populations under study. More precisely, distances are measured in terms of the percentiles in this CDF at which each population's median lies. Δp combines many desirable features of other distance metrics into a single metric; namely, compared to other metrics, p is relatively insensitive to unequal variances and sample sizes among the populations sam- pled. Furthermore, a key feature of Δp—and our main motivation for developing it—is that it easily accommodates simultaneous comparisons of any number of traits across any number of populations. To exemplify its utility, we employ Δp to address a ques- tion related to the role of sexual selection in speciation: are sexual signals more divergent than ecological traits in closely related taxa? Using traits of known function in closely related populations, we show that traits predictive of reproductive performance are, indeed, more divergent and more sexually dimorphic than traits related to ecological adaptation (Current Zoology 58 (3): 426439, 2012).