Thanks Chris. I think what I was thinking of was more on the lines of functional redundancy arising from evolutionary convergence (rather than say gene duplication). As to what exactly is meant by "redundant", you point out interesting variations.
My question originates from RNAi screens. If knockdown of gene X does not result in a loss-of-function phenotype is it because X is not involved in that phenotype? Or is it because X is knocked down, but a functionally equivalent gene (or pathway) can take over the function?
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