Table 2. Mutations in populations V19–4A and V19–4AB after 27 passages in BHK–21 cells ^a.

Genomic region b	Mutation c	Amino acid substitution c	V19–4 population d
L	U1103C	L22P	V19–4B
	A1244G	D69G	V19–4A
VP1	A3649G	T148A	V19–4B
	C3650C/U	T148M	V19–4A
	C3653A/C	T149K	V19–4A
2C	C4507U	R55W	V19–4A
	U4507C e	reversion to R55 e	V19–4B e
	A4597G	I85V	V19–4B
3A	A5573G	E92G	V19–4B
VPg1-coding region	G5779A f	E8K f	V19–4A; V19–4B f
3C	U6534A	—	V19–4B
3D	U7341C/U	—	V19–4A

^aThe consensus sequence of the entire viral genome was determined for FMDV populations V19–4A and V19–4B after 27 passages in cell culture.

^bFMDV genomic region analysed [15].

^cMutations and deduced amino acid substitutions are relative to the sequence of the parental clone FMDV WT (pMT28, described in Materials and Methods); residue numbering is according to [49]. Amino acid residues (single–letter code) are numbered individually for each protein from the N– to the C–terminus. Two residues separated by a bar indicate a mixture of two nucleotides in the population, according to the sequence chromatogram pattern. Procedures for nucleotide sequencing and identification of FMDV genomic regions are described in Materials and Methods.

^dPopulations in which the substitutions indicated in ^c were found.

^eMutation C4507U (that corresponds to amino acid substitution R55W in 2C) was dominant in V19–4B at passage 2 (Table 1) and had reverted by passage 27 (highlighted in italics).

^fSubstitution E8K (G5779A) was found repeated in population V19–4 at passage 27 in series A and B (underlined).