Table 1.

Rate of mutation to sIgM negative

RhA2 (AID-GFP)		Controls
11 B1	7.5	RGFP2	3.2
11 B2	7.5	RGFP2	2.4
11 B3	9.6	RGFP8	4.4
12 B2	12.3
12 B3	8.9
Average*	9.2		3.3

10³ cells per day. 

^*Significance of t test, P < 0.005.