The mutants with two genetic markers, TK15-94-33(a lys- phe-)and TK63-41-72(a ade- leu-), were selected after strains TK15-94 and TK63-41 were treated by EMS.

• EMS诱变后得到带有两个遗传标记的单倍体TK15-94-33(a lys~- phe~-)和TK63，41-72(a ade~- leu~-)。