sentences:  Duplication provides CHS activity with functional redundancy, allowing the "chs" gene to mutate without endangering flavonoid biosynthesis.These divergent enzymes differ from CHS in their preference for starter molecules, the number of acetyl additions (often through malonyl-CoA) and even in the mechanism of ring formation used to cyclize identical polyketide intermediates.The enzyme function of CHS and CHS-like enzymes function very similarly to fatty acid biosynthesis, but without the involvement of acyl-carrier proteins (ACP).