| Species | rRNA | Size (kb) |
|---|---|---|
| Human | 18S | 1.9 |
| 28S | 5.0 | |
| Mouse | 18S | 1.9 |
| 28S | 4.7 | |
| Drosophila | 18S | 2.0 |
| 28S | 4.1* | |
| Tobacco Leaf | 16S | 1.5 |
| 18S | 1.9 | |
| 23S | 2.9 | |
| 25S | 3.7 | |
| Yeast | 18S | 2.0 |
| 26S | 3.8 | |
| E. coli | 16S | 1.5 |
| 23S | 2.9 | |
| Xenopus | 28S | 4.0 |
| 18S | 1.8 |
*Drosophila 28S rRNA is processed into 2 fragments that migrate in a similar manner to the 18S rRNA.