[BioC] Colouring limma MA plot

[adam_pgsql]

I am trying to colour a limma generated MA plot by fold change. I can do it this way:

status <- bugs.colour(RG,1)
attr(status,"values") <- c("nonsignificant", "present", "absent", "Blank", "Buffer", "ACTB", "GAPDH", "Positive")
attr(status,"col") <- c("black", "red", "green", "black", "brown", "pink", "yellow", "orange", "grey")
plotMA(RG, array=1, status=status)

bugs.colour <- function(RG, array) {
    status <- RG$genes$Status
    
    for (i in 1:length(status)) {
        if (status[i] == "gene") {
            if (is.na(RG$other$LogRatio[i,array])) {
                status[i] = "nonsignificant"
            }
            else if (RG$other$LogRatio[i,array] > 0) {
                status[i] = "present"
            }
            else { status[i] = "absent" }
        }
    }
    status
}

but this seems to be a bit of a hack has i have hijacked the control status... my question is, is there a better more efficient way to do this?

thanks

adam