plot_diagnositics: Diagnostic plots for a DESeq differential expression analysis
In mworkentine/mattsUtils: Personal Utility Functions For Various Analysis

Given a valid DESeq results object this function will make a p-value histogram and a volcano plot. The p-value histogram is constructed with the p-values prior to multiple-testing correction and is used to diagnose if something went wrong with your testing procedure. See http://varianceexplained.org/statistics/interpreting-pvalue-histogram/ for more details on interpreting the p-value histogram. The volcano plot gives you an idea of how many genes are differentially expressed in both directions compared to their expression levels.

1	plot_diagnositics(res, cutoff = 0.05, show_title = TRUE)

`res`	A DESeq results object
`cutoff`	The p value to use as a cutoff for significantly differentially expressed genes. Defaults to 0.05
`show_title`	If specified the description of the results object will be printed as the plot's title