. "For example, the methods described by Cadwell et al, PCR Methods and Applications, 2:28???33, 1992, are particularly preferred for use as disclosed herein, with some modifications, as described in the Examples that follow. (Also see Cadwell et al, PCR Methods and Applications, 3(Suppl.):S136???S140, 1994.) According to this modified PCR method, random point mutations may be introduced into cloned" . . .