TABLE 7.

Nucleotide polymorphism^a in the CP cistron before and after nine passages in wheat, barley, or corn

PCR productb	No. of clones sequenced	No. of polymorphic sites/no. of ntc	Mutation frequency/nt
			Uncorrected total	Correctedd total	Correctedd singleton
Reclone	10	3/13,710	2.2 × 10−4	0e	0e
LDSI-S10	17	16/23,307	6.9 × 10−4	4.3 × 10−4	4.3 × 10−4
9BA	13	19/17,823	10.7 × 10−4	8.1 × 10−4	6.4 × 10−4
9WB	20	23/27,420	8.4 × 10−4	5.8 × 10−4	4.0 × 10−4
9CB	15	20/20,565	9.7 × 10−4	7.1 × 10−4	6.6 × 10−4

^aDetermined by sequencing of clones derived from PCR products amplified by EHFS using a DNA template of known sequence. 

^bLDSI-S10 shows polymorphism before passages; 9WB, 9BA, and 9CB show polymorphism after nine passages in wheat, barley, and corn, respectively. 

^cAll identical nonsingletons treated as a single mutation event at one site. 

^dSporadic changes attributed to combined error (2.6 × 10⁻⁴/nt) due to RT (0.36 × 10⁻⁴/nt) and EHFS-PCR error (2.2 × 10⁻⁴/nt) were subtracted to yield corrected mutation frequencies/nucleotide. 

^eAll polymorphism due to in vitro polymerase error during PCR.