Table 1.
ES lines isolated from tissues of implanting strain 129 blastocysts
| Starting material | Total no. of explants | No. giving ES lines (%)* | No. giving male lines† | No. giving female lines |
|---|---|---|---|---|
| Epiblast from 5th-day blastocyst | 48 | 25 (52) | 9 | 13 |
| Endoderm from 5th-day blastocyst | 41 | 0 | — | — |
| Trophectoderm from 5th-day blastocyst | 9 | 0 | — | — |
| Whole ICM from 5th-day blastocyst | 18 | 0 | — | — |
| Fourth-day intact blastocyst (baseline controls) | 31 | 7 (23) | 1 | 5 |
| Single-cell suspension of 5th-day epiblast | 47 | 16 (34)‡ | 9 | 6 |
| Fourth-day intact blastocyst (baseline controls) | 22 | 5 (23) | 3 | 2 |
| ICM from 5th-day blastocyst with outer endoderm layer removed prior to first dissociation | 9 | 0 | — | — |
| Intact ICM from 5th-day blastocyst | 10 | 0 | — | — |
| Fourth-day intact blastocyst (baseline controls) | 12 | 3 (25) | ND | ND |
ND, not determined.
*
Lines were identified morphologically. Details of chimera formation and germline transmission are presented in Table 3.
†
Altogether, five lines were lost before they could be sexed.
‡
One gave two and another three each gave three clonal lines.