<Tr> <Td> </Td> <Td> </Td> </Tr> <P> Ethyl methanesulfonate (EMS) is a mutagenic, teratogenic, and possibly carcinogenic organic compound with formula C H SO . It produces random mutations in genetic material by nucleotide substitution; particularly by guanine alkylation . This typically produces only point mutations . It can induce mutations at a rate of 5x10 to 5x10 per gene without substantial killing . The ethyl group of EMS reacts with guanine in DNA, forming the abnormal base O - ethylguanine . During DNA replication, DNA polymerases that catalyze the process frequently place thymine, instead of cytosine, opposite O - ethylguanine . Following subsequent rounds of replication, the original G: C base pair can become an A: T pair (a transition mutation). This changes the genetic information, is often harmful to cells, and can result in disease . </P> <P> EMS is often used in genetics as a mutagen . Mutations induced by EMS can then be studied in genetic screens or other assays . </P>

Alkylating agents such as ethyl methanesulfonate (ems) function as mutagens to