TABLE 2.

Mutation rate of A/Swine/Germany/2/81

Clone no.	Plaque inhibition assay result (PFU/ml)		Allantoic fluid (ml)	Population size (PFU)a	Mutant frequencyb	Mutation rate (bp/site/replication)c	Quotient (control/ amantadine)	Quotient × 4	Quotient × 4/ genome length
	Control	Amantadine
1	9.2 × 108	1.2 × 105	13.0	1.2 × 1010	1.3 × 10−4	1.9 × 10−6	7.7 × 103	3.1 × 104	2.3
2	6.0 × 108	2.6 × 105	9.0	5.4 × 109	4.3 × 10−4	6.7 × 10−6	2.3 × 103	9.2 × 103	0.7
3	2.3 × 108	1.8 × 105	13.0	3.0 × 109	7.8 × 10−4	1.2 × 10−5	1.3 × 103	5.1 × 103	0.4
4	6.0 × 108	2.6 × 105	11.0	6.6 × 109	4.3 × 10−4	6.6 × 10−6	2.3 × 103	9.2 × 103	0.7
5	1.0 × 109	2.0 × 105	12.0	1.2 × 1010	2.0 × 10−4	3.0 × 10−6	5.0 × 103	2.0 × 104	1.5
6	2.2 × 108	8.0 × 104	10.7	2.4 × 109	3.6 × 10−4	5.8 × 10−6	2.8 × 103	1.1 × 104	0.8
7	4.2 × 108	1.4 × 105	9.3	3.9 × 109	3.3 × 10−4	5.2 × 10−6	3.0 × 103	1.2 × 104	0.9
8	4.0 × 107	4.0 × 104	8.6	3.4 × 108	1.0 × 10−3	1.8 × 10−5	1.0 × 103	4.0 × 103	0.3
9	6.0 × 107	1.8 × 104	9.6	5.8 × 108	3.0 × 10−4	5.2 × 10−6	3.3 × 103	1.3 × 104	1.0
10	3.2 × 107	2.0 × 104	10.5	3.4 × 108	6.3 × 10−4	1.1 × 10−5	1.6 × 103	6.4 × 103	0.5
11	1.0 × 108	1.2 × 104	6.0	6.0 × 108	1.2 × 104	2.1 × 10−6	8.3 × 103	3.3 × 104	2.5
12	4.0 × 108	4.0 × 104	13.5	5.4 × 109	1.0 × 10−4	1.5 × 10−6	1.0 × 104	4.0 × 104	2.9
13	2.8 × 108	2.4 × 105	10.8	3.0 × 109	8.6 × 10−4	1.4 × 10−5	1.2 × 103	4.7 × 103	0.3
14	4.0 × 107	8.0 × 103	8.8	3.5 × 108	2.0 × 10−4	3.5 × 10−6	5.0 × 103	2.0 × 104	1.5
15	1.2 × 108	4.8 × 104	9.0	1.1 × 109	4.0 × 10−4	6.7 × 10−6	2.5 × 103	1.0 × 104	0.7
16	1.3 × 108	1.6 × 104	11.9	1.5 × 109	1.2 × 10−4	2.0 × 10−6	8.1 × 103	3.3 × 104	2.4
17	1.4 × 108	9.6 × 104	9.8	1.4 × 109	6.9 × 10−4	1.1 × 10−5	1.5 × 103	5.8 × 103	0.4
Average	3.1 × 108	1.0 × 105		3.5 × 109	4.2 × 10−4	6.8 × 10−6	3.9 × 103	1.6 × 104	1.2

^aProduct of titer from control and amount of allantoic fluid. 

^bQuotient of titers from plaque inhibition assays with amantadine and control. 

^cRate for each clone calculated from mutant frequency and population size as described in Materials and Methods.