P-N plot
xQTLvisual_PNPlot(summaryDT)
A data.frame with three cols: pval, beta, se.
A ggplot2 object
# \donttest{
url1 <- "https://raw.githubusercontent.com/dingruofan/exampleData/master/eqtl/MMP7_qtlDF.txt"
qtl <- fread(url1, sep="\t")
xQTLvisual_PNPlot(qtl[,.(pValue, beta, se)])
# }