4. A three-point test involving o2, gl1, and ij gave the following counts:
| F1 genotype | 0 | 1 | 2 | 1,2 | Total |
| o2 + + | 467 513 | 115 150 | 94 123 | 28 23 | 1513 |
| + gl1 ij | 980 | 265 | 217 | 51 | |
| 17.5% | 14.3% | 3.4% |
The recombination percentages of o2 and ra1 (repulsion phase), also o2 and gl1 indicate that o2 is to the left of v5 and within 2 or 3 units of v5. The percentages between o2 and ij indicate that o2 is 2 or 3 units to the right of v5.
Stock of o2 is available.