Model code and output for a comparison of methods for meta-analysis investigating covariance between genetic and environmental (CovGE) effects in phenotypic results

The data for the CovGE meta-analysis from the RCN-ECS project were published as dataset \"Metadata for studies from meta-analysis investigating covariance between genetic and environmental (CovGE) effects in phenotypic results (DOI: 10.26008/1912/bco-dmo.877414.1).\" However, this dataset contains a meta-analysis comparing our approach with the method described by Stamp and Hadfield (2020) in Ecology Letters.

The data tables in this dataset contain output of the model described in forthcoming results publication Albecker et al. (n.d.) \"Meta-analysis reveals patterns of cogradient and countergradient variation.\" This results publication used meta-analysis to measure CovGE and GxE across 354 phenotypes within 64 studies.

Katie Lotterhos, with input from the authors, created the \"Behavior_of_PL_metric.Rmd\" file which provides an in-depth comparison of the two measures and contains R code and rendered figures created with R-Markdown (.Rmd). Dr. Lotterhos documented code and interpretation to demonstrate similarities and contrasts among the two approaches (see Supplemental File \"Behavior_of_PL_metric.pdf\"). She also uses subsets of simulated data to demonstrate how the two approaches calculate CovGE or PL metric using the same data.

RCN-ECS项目的CovGE元分析相关数据，以数据集"探究表型结果中遗传与环境效应协方差（CovGE）的元分析研究元数据"（DOI: 10.26008/1912/bco-dmo.877414.1）的形式公开发布。不过，该数据集还包含一项元分析，用于对比本研究方法与Stamp和Hadfield于2020年在《Ecology Letters》（生态学快报）中提出的分析方法。

本数据集的数据表均来自即将发表的成果论文Albecker等人（无出版日期）"元分析揭示协梯度与逆梯度变异模式"中所述模型的输出结果。该论文通过元分析方法，对64项研究中的354个表型的CovGE与基因型-环境互作（GxE，genotype-environment interaction）效应进行了量化分析。

在作者团队的协助下，Katie Lotterhos编写了"Behavior_of_PL_metric.Rmd"文件，该文件对两种分析方法展开了深入对比，其中包含R代码与通过R-Markdown（.Rmd）渲染生成的可视化图表。Lotterhos博士对代码与解读文档进行了整理，以清晰展示两种分析方法的异同之处（详见补充文件"Behavior_of_PL_metric.pdf"）。此外，她还借助模拟数据的子集，演示了两种方法如何基于同一数据集分别计算CovGE与PL指标。