Alkylation (addition of a methyl
or ethyl group) of the 6'-O position
in Guanine leaves only two sites
for
H-bonds: O-6-ethyl-G
pairs
with T
instead of C.
Ethyl
Methane
Sulfonate (EMS) is commonly use to mutagenize Drosophila and other laboratory organisms,
since it
can be incorporated directly into food.