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把显著性添加给玩明白

把显著性添加给玩明白

作者: 小洁忘了怎么分身 | 来源:发表于2023-08-16 16:07 被阅读0次

    1.编示例数据

    set.seed(10086)
    exp = matrix(rnorm(480,mean = 6),ncol = 120)
    exp = round(exp,2)
    rownames(exp) = paste0("gene",1:4)
    colnames(exp) = paste0("test",1:120)
    exp[,50:80] = exp[,50:80]+2
    exp[,90:120] = exp[,90:120]+4
    exp[1:4,1:4]
    
    ##       test1 test2 test3 test4
    ## gene1  6.55  5.37  6.32  4.18
    ## gene2  3.26  6.25  5.63  5.78
    ## gene3  6.57  6.80  8.11  6.58
    ## gene4  6.49  7.08  8.49  4.38
    

    到这一步,拿到了一个编的表达矩阵。

    2.格式转换

    表达矩阵要画ggplot2箱线图,肯定是要先转变格式的,否则ggplot2代码无法下手写。

    library(tidyr)
    library(tibble)
    library(dplyr)
    dat = t(exp) %>% 
      as.data.frame() %>% 
      rownames_to_column() %>% 
      mutate(group = rep(c("control","treat1","treat2"),each = 40))
    
    pdat = dat%>% 
      pivot_longer(cols = starts_with("gene"),
                   names_to = "gene",
                   values_to = "value")
    head(pdat)
    
    ## # A tibble: 6 × 4
    ##   rowname group   gene  value
    ##   <chr>   <chr>   <chr> <dbl>
    ## 1 test1   control gene1  6.55
    ## 2 test1   control gene2  3.26
    ## 3 test1   control gene3  6.57
    ## 4 test1   control gene4  6.49
    ## 5 test2   control gene1  5.37
    ## 6 test2   control gene2  6.25
    

    3.画箱线图

    library(ggplot2)
    p1 = ggplot(pdat, aes(y=value, x=gene))+
      geom_boxplot(aes(fill=group),outlier.shape = NA)+
      theme_bw()+
      scale_fill_manual(values = c("#2fa1dd", "#f87669", "#e6b707"))
    p1
    

    [图片上传失败...(image-382a55-1692258856792)]

    p2 = ggplot(pdat, aes(y=value, x=gene))+
      geom_bar(aes(fill=group),position = position_dodge(0.9),stat = "summary")+
      theme_bw()+
      scale_fill_manual(values = c("#2fa1dd", "#f87669", "#e6b707"))+
      stat_summary(aes(group = group), fun.data = 'mean_se', 
                   geom = "errorbar", colour = "black",
                   width = 0.2,position = position_dodge(0.9))
    
    p2
    

    [图片上传失败...(image-297a28-1692258856792)]

    4.加显著性标记

    4.1习以为常版

    library(ggpubr)
    p1 + 
      stat_compare_means(aes(group = group, label = after_stat(p.signif)),method = "wilcox.test")
    

    [图片上传失败...(image-ee95bd-1692258856792)]

    p2 + stat_compare_means(aes(group = group, label = after_stat(p.signif)),method = "wilcox.test",label.y = 10.5)
    

    [图片上传失败...(image-2a7112-1692258856792)]

    这个超级简单,但显著性统一在头顶上,然后也不支持每个基因在两两分组中的显著性单独计算。

    4.2 错落有致版

    用rstatix里的函数计算出显著性和添加显著性的横纵坐标位置,再用stat_pvalue_manual添加上去。

    library(rstatix)
    stat.test <- pdat %>% 
      group_by(gene) %>% 
      wilcox_test(value ~ group) %>%
      adjust_pvalue() %>% 
      add_significance("p.adj") %>% 
      add_xy_position(x="gene")
    p1 + stat_pvalue_manual(stat.test,label = "p.adj.signif",hide.ns = F,
                       tip.length = 0.01)
    

    [图片上传失败...(image-241141-1692258856792)]

    p2 + stat_pvalue_manual(stat.test,label = "p.adj.signif",hide.ns = F,
                       tip.length = 0.01)
    

    [图片上传失败...(image-16df19-1692258856792)]

    4.3 手动添加版

    例如上次画的AUC值柱状图,它的纵坐标和误差棒不是画图时计算出来的,而是拿了现成的数值来画,就无法用上面的方法计算。如果能自行用其他方法计算出组间比较的显著性如何,可以手动添加。

    rm(list = ls())
    load("dats.Rdata")
    p = ggplot(dats, aes(x = category, y = y, fill = x)) +
      geom_bar(stat = "identity", position = "dodge") +
      geom_text(aes(label = round(y,2)), vjust = 4, size = 3,
                position = position_dodge(width = 0.9)) +
      geom_errorbar(aes(ymin = min, ymax = max), 
                    width = 0.2,
                    position = position_dodge(width = 0.9)) +
      scale_fill_manual(values = c("#2fa1dd", "#f87669", "#e6b707"))+
      theme_bw()
    p
    

    [图片上传失败...(image-c65f9d-1692258856792)]

    p +   geom_signif(data = dats,y_position=c(1,0.97,0.83,0.89,0.89,0.92), 
                  xmin=c(0.7,1,1.7,2,2.7,3), 
                  xmax=c(1,1.3,2,2.3,3,3.3), 
                  annotation=c("*","**","***","ns","*","**"), 
                  tip_length=0.01, 
                  vjust = 0.3)
    

    [图片上传失败...(image-75aa38-1692258856791)]

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