2.3.2. Chemical Mutagens
It would be about two decades after the demonstrations of the mutagenicity of physical agents that nitrogen mustard (component of poisonous mustard gas used in World Wars I and II) would be shown to cause mutations in cells [30–38]. This would pave the way for the identification of several other chemical mutagens; these include base analogues, alkylating and intercalating agents and chemicals that modify DNA structure. Their effects on DNA molecules manifest in deamination, the induction of transitions and insertions, the stoppage of transcription and replication and even strand breaks. The properties of the chemical agents commonly used for inducing mutations in crops are shown in Table 3.