Table 5.
The phylogenetic distribution of nonsilent (NS) substitutions on trees constructed using only sequences from egg-cultured or cell-cultured isolates and using only non-HM codons
| Number of branches | Exp NS | Obs NS | χ2 | |
|---|---|---|---|---|
| Branches on egg tree | ||||
| Terminal | 152 | 119.3 | 155 | 10.7 |
| Internal | 150 | 117.7 | 82 | 10.8 |
| Total | 302 | 237.0 | 237 | 21.5 |
| Branches on cell tree | ||||
| Terminal | 148 | 121.3 | 158 | 11.1 |
| Internal | 146 | 119.7 | 83 | 11.2 |
| Total | 294 | 241.0 | 241 | 22.3 |
Trees constructed without the HM codons using sequences from isolates propagated in egg culture or in cell culture both showed significant excesses of nonsilent substitutions on their terminal branches (P < 0.05, df = 1 for both tests). The percent excess of nonsilent substitutions on the terminal branches was 30% for both the egg and cell trees.