TABLE 1.

Mutation rate ofA/Mallard/New York/6750/78

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	1.6 × 107	1.2 × 104	7.0	1.1 × 108	7.5 × 10−4	1.4 × 10−5	1.3 × 103	5.3 × 103	0.4
2	4.0 × 107	3.2 × 104	9.1	3.6 × 108	8.0 × 10−4	1.4 × 10−5	1.3 × 103	5.0 × 103	0.4
3	1.0 × 107	1.2 × 104	7.1	7.1 × 107	1.2 × 10−3	2.3 × 10−5	8.3 × 102	3.3 × 103	0.2
4	2.9 × 107	1.2 × 104	7.8	2.3 × 108	4.1 × 10−4	7.5 × 10−6	2.4 × 103	9.7 × 103	0.7
5	2.0 × 107	4.4 × 104	8.5	1.7 × 108	2.2 × 10−3	4.0 × 10−5	4.5 × 102	1.8 × 103	0.1
6	9.6 × 106	1.6 × 104	13.3	1.3 × 108	1.7 × 10−3	3.1 × 10−5	6.0 × 102	2.4 × 103	0.2
7	6.8 × 107	8.0 × 103	9.3	6.3 × 108	1.2 × 10−4	2.0 × 10−6	8.5 × 103	3.4 × 104	2.5
8	8.4 × 107	4.0 × 104	10.4	8.7 × 108	4.8 × 10−4	8.0 × 10−6	2.1 × 103	8.4 × 103	0.6
9	3.2 × 107	3.2 × 105	7.9	2.5 × 108	1.0 × 10−2	1.8 × 10−4	1.0 × 102	4.0 × 102	0.0
10	1.1 × 108	4.0 × 103	13.6	1.5 × 109	3.6 × 10−5	6.0 × 10−7	2.8 × 104	1.1 × 105	8.1
Average	4.2 × 107	5.0 × 104		4.3 × 108	1.8 × 10−3	3.2 × 10−5	4.5 × 103	1.8 × 104	1.3

^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.