Table 3. The efficiency to obtain ESC mice by tetraploid complementation.
| Blastocysts | ESCs | No. embryos transferred | No. surrogates | No. live pups (%) | No. herniated pups (%) |
| Type a | 2nESCs | 415 | 20 | 59(14.2) | 4(6.8)* |
| Type b | 2nESCs | 384 | 19 | 41(10.7) | 28(68.3) |
| Type a | Co-injection 2nESCs 4nESCs | 106 | 6 | 12(11.3) | 0 |
| Type b | Co-injection 2nESCs 4nESCs | 52 | 3 | 5(9.6) | 2(40.0) |
*χ2-test, P<0.01.Percentage of live pups (%) = No. live pups/No. embryos* 100%; Percentage of herniated pups(%) = No. herniated pups/No. live pups*100%; Co-injection of 2nESCs and 4nESCs into tetraploid blastocysts, each blastocysts received at least ten 2nESCs and ten 4nESCs.