Before revision:  For that, we perform an exhaustive computational screening of synthetic lethal reaction pairs in Escherichia coli in  minimal medium and  find that synthetic lethals divide in two different groups depending on whether the synthetic lethal interaction works as a back up or as a parallel use mechanism, the first corresponding to essential plasticity and the second to essential redundancy.
After revision:  We perform an exhaustive computational screening of synthetic lethal reaction pairs in Escherichia coli in minimal medium and find that synthetic lethals divide in two different groups depending on whether the synthetic lethal interaction works as a back up or as a parallel use mechanism, the first corresponding to essential plasticity and the second to essential redundancy.