Table 1.

Frequency and average rate of Fc-fragment secretion by single cells in wild-type P. pastoris and mutagenized polyclonal daughter populations

Strain or round of mutagenesis	Frequency of secreting cells (%)	Rate of secretion (ng · ml−1 · h−1)
		Median	Mean
Nonmutagenized parent strain	69	3.0a	3.8
1	80	1.8	2.4
2	73	2.2	3.1
3	84	4.5a	6.3

^aThese data were subjected to a Mann-Whitney test (P < 0.0001).