TABLE 4.

Calculated ages of fully sequenced strains and their hypothetical common precursor

Strain genome	Age (mo) of genomic regiona
	P1			P2/P3		Entire genome
	a	b	c	a	b	a	b
CPb	0.0	0.0	0.0	1.1	1.0	0.6	0.4
PT1	1.4	1.0	2.0	1.7	2.0	1.7	1.7
PT1-1	0.6	0.4	0.8	2.3	2.5	1.7	1.7
PT1-2	2.5	2.1	3.6	4.6	5.1	3.7	3.5
PT2	1.4	1.0	2.0	2.3	2.5	2.0	2.2
PT3/PT4	2.8	2.5	4.0	3.4	4.0	3.1	3.0
PT3-1	2.8	2.8	4.0	3.4	4.0	3.1	3.5
C-1	3.3	2.8	4.8	3.1	3.5	3.1	3.0
C-2	1.4	1.0	2.0	3.1	3.5	2.2	2.2

^aThe letters a, b, and c correspond to the ages calculated using the parameters or sequences reported in references 17, 18, and 19, respectively.

^bThe CP genome was assumed to be represented by the Sabin 2 RNA with 6 acquired mutations (Fig. 2).