Table 1.

Different estimates of the ancestral divergence and the substitution rate

Gene fragment	Pairwise*	Branch†	Resample‡	External§
Ancestral divergence, Da
env V3	29.6	na	27.4  ±  7.0	21.3
p17 gag	7.7	na	6.6  ±  4.2	4.3
Substitution rate, β
env V3	6.9	7.0	6.7  ±  2.1	6.6
p17 gag	2.5	2.8	2.7  ±  0.5	2.9

As discussed in the text, our best estimates are in bold. na, not applicable. Values are based on × 10⁻³. 

^*Value based on a linear regression line fitted to all pair-wise branch distances (Fig. 4). 

^†Value based on a linear regression line fitted to all individual branch segments (Fig. 3B). 

^‡Value based on resampled pair-wise distances as described in Materials and Methods. 

^§Value based on a linear regression line fitted to external branch segments only (Fig. 3B).