library(ggplot2)

R2_04_1 <- ggplot(mtcars, aes(factor(cyl))) + 

  geom_bar(aes(fill = factor(gear)), width = 0.6) + 

  labs(title = "Here is title", subtitle = "Here is subtitle", caption = "R2-04", x = "cyl", fill = "gear") # 更改图例名p1

mytheme <- theme_classic() +

           theme(panel.grid.major = element_blank(),   

                 legend.position = "none",

                 plot.caption = element_text(face = "bold.italic"))

R2_04_1 + mytheme

library("ggplot2")

library("latex2exp") 

library(ggrepel)

volcano_data <- read.csv(file.choose())       

volcano_data$significant <- ifelse(abs(log2(volcano_data$FC)) < 1 | volcano_data$q_value > 0.05 ,"not","yes" )

volcano_data$mylabels <- ifelse(abs(log2(volcano_data$FC)) < 1| volcano_data$q_value > 0.05,NA,as.character(volcano_data$Gene.ID))

sig <- subset(volcano_data,significant == "yes")

R2_04_2 <- ggplot(volcano_data,aes(x = log2(FC) , y = -log2(q_value),size = significant)) + 

          geom_point(col = "grey") +  

          xlim(-2.5,2.7) +

          ylim(-0.4,15) +

          scale_size_manual(values = c(2,0)) +

          geom_point(data = sig,aes(x = log2(FC),y = -log2(q_value),col = mylabels),size = 4) + 

          geom_text_repel(aes(label = mylabels),size =3,col = "black",fontface = "italic") +  

  annotate("segment", x = 1 , xend = 2.5, y = 1,yend  = 1 ,color = "black",

           size = 1,arrow = arrow(angle = 18,ends = "last",type = "closed")) +

  annotate("segment", x = -1 , xend = -2.5, y = 1,yend  = 1 ,color = "black",

           size = 1,arrow = arrow(angle = 18,ends = "last",type = "closed")) +

  annotate("text",x = 1.7,y = 1.9,label = "Upregulated",size = 4.5) +

  annotate("text",x = -1.7,y = 1.9,label = "Downregulated",size = 4.5)  +

  labs(title = "CMTM6 sgRNA2 vs Control",

       caption = "create by R2-04") +    

  labs(x = expression(log[2])) +

  labs(x = expression(paste(log[2],"(fold change)")),

       y = expression(paste(-log[2],"(Q value)")))

R2_04_2 + 

  theme(plot.title = element_text(hjust = mean(range(log2(volcano_data$FC)))+ 0.1)) +

  geom_vline(xintercept = 0,linetype = 2 ,size= rel(0.8)) +  

  mytheme 

我觉得群主新建一个数据框，来放置标注的六个基因是正解。但是，鉴于我好不容易才找到ggrepel包，给大家推荐一下