"get.go.root" <-
function(ont)
{
	if(ont == "BP")
		return("GO:0008150")
	else if(ont == "MF")
		return("GO:0003674")
	else if(ont == "CC")
		return("GO:0005575")
	else
		stop("Invalid ontology (must be one of 'BP','MF', or 'CC')")
}