理解分析结果并撰写科研论文
工具名称:两组/多组比较横向柱形图
本工具用于分析微生物组数据中的差异特征(如OTU、ASV、物种或功能基因),支持两组或多组比较。它提供了多种统计检验方法,并对结果进行多重检验校正,同时生成直观的可视化图表。
行是特征(如微生物物种),列是样本。应为制表符分隔的文本文件。
包含样本的分组信息,第一列为样本ID,应与丰度表中的列名对应。
工具首先对丰度表进行预处理:
根据组数选择合适的统计方法:
| 比较类型 | 默认统计方法 | 备选方法 | 适用条件 |
|---|---|---|---|
| 两组比较 | Mann-Whitney U检验 | t检验 | 非正态分布数据 |
| 多组比较 | Kruskal-Wallis检验 | ANOVA | 多组间整体差异检验 |
为控制假阳性率,工具默认使用FDR(False Discovery Rate)校正:
除了p值,工具还计算两种效应量:
分析完成后,会生成以下文件:
两组比较结果表格包含以下列:
| 列名 | 含义 | 解读指南 |
|---|---|---|
| feature | 特征名称 | 差异显著的微生物或功能特征 |
| Experimental, Control | 各组平均丰度 | 特征在实验组和对照组中的平均相对丰度 |
| pvalue | 原始p值 | 统计检验的原始显著性水平 |
| padj | 校正后p值 | 经多重检验校正后的p值(更可靠) |
| diff | 均值差异 | 实验组 - 对照组的平均丰度绝对差异 |
| ci_low, ci_high | 95%置信区间 | 差异估计的不确定性范围 |
| log2FoldChange | 对数倍数变化 | log2(实验组/对照组),正值为实验组中上调,负值为对照组中上调 |
| effect_size | 效应量(Hedges' g) | 标准化的组间差异大小 |
两组比较可视化图表包含四个主要部分:
解读提示:关注校正后p值<0.05的特征,同时考虑效应量大小。
多组比较结果表格包含以下列:
| 列名 | 含义 | 解读指南 |
|---|---|---|
| feature | 特征名称 | 差异显著的微生物或功能特征 |
| Group1, Group2, ... | 各组平均丰度 | 特征在各组中的平均相对丰度 |
| pvalue | 原始p值 | Kruskal-Wallis检验的原始显著性水平 |
| padj | 校正后p值 | 经多重检验校正后的p值 |
多组比较可视化图表展示各特征在不同组中的平均丰度:
注意:多组比较仅检验组间整体差异
To identify differentially abundant microbial features between groups, we performed statistical analysis using the "Two-Group Comparison Horizontal Bar Chart" tool. The raw abundance table was preprocessed by filtering features with prevalence below 20%, filling zeros with half of the minimum non-zero value, and applying log10 transformation to reduce skewness.
Differential abundance between the experimental and control groups was assessed using the Mann-Whitney U test. To control for false discovery rate (FDR) in multiple testing, we applied the Benjamini-Hochberg correction. Effect sizes were calculated as Hedges' g and log2 fold change (log2FC) to quantify the magnitude of differences. Statistical significance was defined as FDR-adjusted p-value < 0.05.
Comparative analysis revealed [X] significantly differentially abundant microbial features between the experimental and control groups (FDR < 0.05). Among these, [Y] features were significantly enriched in the experimental group (e.g., [Feature1], log2FC = [value], p_adj = [value]), while [Z] features were enriched in the control group (e.g., [Feature2], log2FC = [value], p_adj = [value]). Effect size analysis indicated that [Feature3] showed the largest between-group difference (Hedges' g = [value]).
Figure X. Differentially abundant microbial features between experimental and control groups.
(A) Horizontal bar chart showing mean relative abundance of features in the experimental group (user-defined color) and control group (user-defined color).
(B) Difference plot displaying between-group differences with 95% confidence intervals (error bars).
(C) Effect size (Hedges' g) plot, with points farther from zero indicating larger effect sizes.
(D) Fold change (log2FC) plot, with positive values indicating enrichment in the experimental group.
FDR-adjusted p-values and significance levels are shown on the right (*p < 0.05, **p < 0.01, ***p < 0.001).
To identify differentially abundant microbial features across multiple groups, we employed the "Multi-Group Comparison Horizontal Bar Chart" tool. Data preprocessing included filtering features with prevalence below 20%, zero-value imputation, and log10 transformation.
Global differences among groups were tested using the Kruskal-Wallis test, with FDR adjustment using the Benjamini-Hochberg method. Statistical significance was defined as FDR-adjusted p-value < 0.05.
The Kruskal-Wallis test identified [X] microbial features with significant abundance differences across [GroupA], [GroupB], and [GroupC] (FDR < 0.05). Specifically, [Feature1] showed highest abundance in [GroupA] (mean abundance = [value]), while [Feature2] was most abundant in [GroupC] (mean abundance = [value]). These differentially abundant features may reflect group-specific microbial composition patterns.
Figure X. Differentially abundant microbial features across multiple groups.
Horizontal bar chart displaying mean relative abundance of the top [N] most significant features across groups, with different colors representing different groups (colors user-defined). FDR-adjusted p-values from Kruskal-Wallis test and significance levels are shown on the right (*p < 0.05, **p < 0.01, ***p < 0.001).
The significant enrichment of [FeatureX] in the experimental group may be associated with [biological process]. Previous studies have reported similar patterns of [FeatureX] abundance under [similar conditions] [citation]. Additionally, the enrichment of [FeatureY] in the control group might reflect [adaptive response]. These differentially abundant microbial features could serve as potential biomarkers worthy of further investigation into their functional significance.
Note: The discussion should integrate specific research context and existing literature to explain the biological significance of differential features.
重要注意事项:
最佳实践建议: