volcanoplot.R

library(ggplot2)

# plot volcano plot
res <- read.table("Male_vs_Female_Pre", head=TRUE)
res$Significant <- ifelse(res$adj.P.Val < 0.05, "adj.P.Val < 0.05", "Not Significant")
ggplot(res, aes(x = logFC, y = -log10(P.Value))) +
  geom_point(aes(color = Significant)) +
  scale_color_manual(values = c("red", "grey")) +
  theme_bw(base_size = 12) + theme(legend.position = "bottom") +
  geom_text_repel(
    data = subset(res, adj.P.Val < 0.05 & abs(logFC)>4),
    #data = subset(res, abs(logFC)>4),
    aes(label = gene),
    size = 3,
    box.padding = unit(0.35, "lines"),
    point.padding = unit(0.3, "lines")
  ) +
  ggtitle("Men vs Women")+ 
  theme(plot.title = element_text(hjust = 0.5))