N each cluster co-evolved (results not shown). WhiJ paralogues in S. coelicolor vary considerably in their conservation in other organisms. One (SCO3421) was present in nearly all complex actinomycetes, and the adjacent gene encoding a likely antisigma factor nearly always contained a TTA codon in Streptomycineae (but in no other groups). Another present in all Streptomycineae (SCO4441) was also w