Table 17.1.

Summary of selection method

Cell type	Transfection method	Selection markers	Round 1 selection	Days until die-off begins	Round 2 selection
CHO dhfr–	Electroporation	pSV2-dhfr	Alpha MEM, 5% D-FBS	12–14	Alpha MEM, 5% D-FBS, MTX (0.1–0.4 mM)
LEC1	Electroporation	pcDNA3.1, pSV2-dhfr	Alpha MEM, 5% FBS, 0.5 mg ml−1 geneticin	15–17	Alpha MEM, 5% D-FBS, MTX (0.025–0.1 mM)
HEK 293 GnTi-	PEI	pcDNA3.1	DMEM:F12, 5% FBS, 2 mg ml−1 geneticin	7–10	N/A
CHO-S	PEI	pcDNA3.1	DMEM:F12, 5% FBS, 0.5 mg ml−1 geneticin	7–10	N/A