[BioC] How to create a heatmap of a gene family (using subset of exprs(vsd) in DESeq)

[Theresa Hodges [guest]]

I have been using DESeq to look at differential gene expression and have run into a problem creating heatmap plots of my data.   I am able to create a heatmap of my top 100 expressed genes using the following code:   

select=order(rowMeans(counts(cds)), decreasing=TRUE)[1:100]
hmcol=colorRampPalette(brewer.pale(9, "GnBu"))(100)
heatmap.2(exprs(vsd)[select, ], col=hmcol, trace="none", margin=c(10,6))

I would also like to create a separate heatmap for 4 gene families, such as the olfactory receptors, and have already replaced the gene id with the gene name for my families of interest.  For example, all olfactory receptors' ids in my dataset of 13,500 genes now start with OR (OR1, OR50, etc). Can you tell me how I can modify the above code to create a subset of the exprs(vsd) containing just the ORs and a heatmap to display the ORs?  I am new to R so I'm not sure if this is possible.

Thank you in advance.  

Theresa
 

 -- output of sessionInfo(): 

select=order(rowMeans(counts(cds)), decreasing=TRUE)[1:100]
hmcol=colorRampPalette(brewer.pale(9, "GnBu"))(100)
heatmap.2(exprs(vsd)[select, ], col=hmcol, trace="none", margin=c(10,6))

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